Senior 4 min · March 06, 2026

Profit and Loss Problems — Profit% on SP Cost ₹2 Lakh

Q: What is the difference between profit percentage and markup percentage?

Both are calculated on Cost Price — they're actually the same thing. Markup % and Profit % both equal (SP − CP) / CP × 100. The word 'markup' is just the retail industry's term for profit percentage. Be careful though: Discount % is calculated on Marked Price, not CP — that's the one that differs.

Q: How do I find the cost price when only the selling price and profit percentage are given?

Use the formula: CP = SP × 100 / (100 + Profit%). For example, if SP is ₹1,100 and profit is 10%, then CP = 1100 × 100 / 110 = ₹1,000. The logic is that SP represents (100 + Profit%) parts, so you scale back down to 100 parts to find CP.

Q: Why is there always a loss when two items are sold at the same price — one at X% profit and one at X% loss?

Because the cost prices are different. The item sold at a loss had a higher cost price (you paid more for it), while the item sold at a profit had a lower cost price. When you add the two cost prices together, the total always exceeds the total selling price. The net loss is exactly X²/100 percent — for 10%, that's 1%. You can only avoid this by selling at the same COST price, not the same selling price.

Q: Can the net % shortcut (M − D − (M×D)/100) be used for any two successive percentage changes?

Yes! It works for any two successive percentage changes applied to a base value, whether they are profits, losses, discounts, or markups. Just be careful with signs: profit/markup is positive, loss/discount is negative. The formula automatically handles the sign if you plug in the correct signed value (e.g., for a loss use −L% instead of L%).

Profit% on SP instead of CP cost a retail chain ₹2 lakh.

Naren · Founder

Plain-English first. Then code. Then the interview question.

About

● Production Incident 🔎 Debug Guide

⚡Quick Answer

Profit and loss problems test your ability to compute gains and losses from buying and selling.
The four foundation terms: Cost Price (CP), Selling Price (SP), Profit, Loss.
Profit% and Loss% are always calculated on CP — not SP. This is the #1 mistake.
Use formulas: SP = CP × (1 ± P%/100) and reverse formulas for CP.
For combined markup and discount, net % = M − D − (M×D)/100.
Always verify by working backwards to catch arithmetic errors.

Plain-English First

Imagine you buy a cricket bat for ₹500 and sell it to your friend for ₹600. You made ₹100 extra — that's your profit. Now flip it: you bought it for ₹500 but had to sell it for ₹400 because no one wanted it — that ₹100 you lost is called a loss. Profit and loss is literally just the story of buying something and selling it, and figuring out whether you came out ahead or behind.

Every business on the planet — from a street-side chai stall to Amazon — lives and breathes profit and loss. When a shopkeeper marks up a price, offers a discount, or sells goods in bulk, they're doing profit and loss calculations in their head. These aren't abstract math problems; they're the engine of commerce. That's exactly why aptitude tests and technical interviews use them: they reveal whether you can think clearly about numbers under pressure.

The Four Foundation Terms You Must Know Cold

Before you touch a single formula, you need to own these four terms. Confusing any two of them is the #1 reason candidates lose marks.

Cost Price (CP): The price at which you BUY something. This is your investment. If you bought a phone for ₹10,000, your CP is ₹10,000.

Selling Price (SP): The price at which you SELL something. If you sold that phone for ₹12,000, your SP is ₹12,000.

Profit: When SP > CP. You sold for MORE than you paid. Profit = SP − CP.

Loss: When CP > SP. You sold for LESS than you paid. Loss = CP − SP.

Here's the anchor image to burn into memory: think of CP as the floor. If your SP is above the floor, you're in profit territory. If it's below the floor, you're in a hole — a loss. Everything in profit and loss revolves around the relationship between these two numbers. Get this instinct right and every formula that follows will feel obvious, not memorised.

FoundationConcepts.txtINTERVIEW

=== PROFIT AND LOSS — FOUNDATION FORMULAS ===

Given:
  Cost Price (CP)    = ₹10,000   ← what you paid to buy the phone
  Selling Price (SP) = ₹12,000   ← what you got when you sold it

Step 1 — Identify whether it's Profit or Loss:
  SP (12,000) > CP (10,000)  →  It's a PROFIT situation

Step 2 — Calculate Profit:
  Profit = SP − CP
         = 12,000 − 10,000
         = ₹2,000

Step 3 — Calculate Profit %:
  Profit % = (Profit / CP) × 100
           = (2,000 / 10,000) × 100
           = 20%

──────────────────────────────────────────
Now flip it — Loss scenario:
  CP = ₹10,000
  SP = ₹8,500

  CP (10,000) > SP (8,500)  →  It's a LOSS situation

  Loss = CP − SP
       = 10,000 − 8,500
       = ₹1,500

  Loss % = (Loss / CP) × 100
         = (1,500 / 10,000) × 100
         = 15%

══════════════════════════════════════════
KEY RULE: Profit % and Loss % are ALWAYS
calculated on the COST PRICE — not the
Selling Price. Forgetting this = wrong answer.
══════════════════════════════════════════

Output

Profit scenario → Profit = ₹2,000 | Profit % = 20%

Loss scenario → Loss = ₹1,500 | Loss % = 15%

Watch Out:

Profit % and Loss % are calculated on the COST PRICE, not the Selling Price. This is the single most common mistake in aptitude tests. When a question says '20% profit', it means 20% of what you PAID — not 20% of what you sold it for.

Production Insight

In a real business, misidentifying the base shifts profit projections by millions.

Accountants always use cost price as the denominator — it's the investment.

Rule: always ask 'what did I pay?' and use that as the denominator.

Key Takeaway

Profit% and Loss% are ALWAYS on Cost Price.

Forgetting this is the #1 exam mistake.

Anchor to CP: it's your investment.

Is it Profit or Loss?

IfSP > CP

→

UseProfit = SP − CP; Profit% = (Profit/CP)×100

IfCP > SP

→

UseLoss = CP − SP; Loss% = (Loss/CP)×100

IfSP == CP

→

UseNo profit, no loss (break-even)

The Master Formula Sheet — Every Variation in One Place

Once you know CP and SP, everything else is derived. Here's every formula you'll ever need, explained with the reasoning behind each one.

Finding SP when CP and Profit% are given: SP = CP × (1 + Profit%/100) Think of it as: SP = CP + (Profit% of CP). You're adding the gain on top.

Finding SP when CP and Loss% are given: SP = CP × (1 − Loss%/100) You're subtracting the loss from what you paid.

Finding CP when SP and Profit% are given: CP = SP × 100 / (100 + Profit%) You're reverse-engineering the original price.

Finding CP when SP and Loss% are given: CP = SP × 100 / (100 − Loss%)

These four formulas handle 90% of all profit and loss questions. The trick is recognising WHICH two pieces of information the question gives you, then picking the right formula. Always label what you KNOW and what you NEED before you start calculating.

MasterFormulaWorkthrough.txtINTERVIEW

=== WORKED PROBLEMS — ALL 4 FORMULA TYPES ===

─────────────────────────────────────────────
PROBLEM 1: Find SP
  "A shopkeeper buys a bag for ₹800 and wants
   to make a 25% profit. What should he sell it for?"

  Known: CP = ₹800, Profit% = 25
  Need:  SP = ?

  Formula: SP = CP × (1 + Profit%/100)
         SP = 800 × (1 + 25/100)
         SP = 800 × (1 + 0.25)
         SP = 800 × 1.25
         SP = ₹1,000

  ✓ Check: Profit = 1000 − 800 = 200
            Profit% = (200/800) × 100 = 25% ✓
─────────────────────────────────────────────
PROBLEM 2: Find SP (Loss)
  "A TV bought for ₹15,000 is sold at a 10% loss.
   Find the selling price."

  Known: CP = ₹15,000, Loss% = 10
  Need:  SP = ?

  Formula: SP = CP × (1 − Loss%/100)
         SP = 15,000 × (1 − 10/100)
         SP = 15,000 × 0.90
         SP = ₹13,500
─────────────────────────────────────────────
PROBLEM 3: Find CP (given SP and Profit%)
  "A watch is sold for ₹1,320 at a profit of 10%.
   What was the cost price?"

  Known: SP = ₹1,320, Profit% = 10
  Need:  CP = ?

  Formula: CP = SP × 100 / (100 + Profit%)
         CP = 1,320 × 100 / (100 + 10)
         CP = 132,000 / 110
         CP = ₹1,200

  ✓ Check: Profit = 1320 − 1200 = 120
            Profit% = (120/1200) × 100 = 10% ✓
─────────────────────────────────────────────
PROBLEM 4: Find CP (given SP and Loss%)
  "A laptop is sold for ₹34,000 at a loss of 15%.
   Find the original cost price."

  Known: SP = ₹34,000, Loss% = 15
  Need:  CP = ?

  Formula: CP = SP × 100 / (100 − Loss%)
         CP = 34,000 × 100 / (100 − 15)
         CP = 3,400,000 / 85
         CP = ₹40,000

  ✓ Check: Loss = 40,000 − 34,000 = 6,000
            Loss% = (6,000/40,000) × 100 = 15% ✓

Output

Problem 1 → SP = ₹1,000 (25% profit on ₹800)

Problem 2 → SP = ₹13,500 (10% loss on ₹15,000)

Problem 3 → CP = ₹1,200 (SP ₹1,320 at 10% profit)

Problem 4 → CP = ₹40,000 (SP ₹34,000 at 15% loss)

Pro Tip:

Always verify your answer by working backwards. If you found CP, plug it back in to confirm Profit% or Loss% matches the question. This takes 10 seconds and catches arithmetic errors before they cost you the mark.

Production Insight

Pricing errors in e-commerce shops often come from misapplying these formulas.

A 20% profit target on a ₹500 item should give SP = ₹600, not ₹520.

Rule: write down the formula before plugging numbers — muscle memory isn't enough.

Key Takeaway

Label what you KNOW and what you NEED.

Then pick the formula that connects them.

Never start calculating without this step.

Which Formula Do I Use?

IfGiven CP and Profit% (or Loss%)

→

UseUse SP = CP × (1 ± %/100)

IfGiven SP and Profit% (or Loss%)

→

UseUse CP = SP × 100 / (100 ± %)

IfGiven CP and SP

→

UseCompute profit/loss amount, then % on CP

Marked Price, Discounts and the Real-World Shop Problem

Real interviews love adding one more layer: the concept of Marked Price (MP) and Discount. Here's where it gets interesting.

Marked Price (MP): The price tag on the shelf — what the seller ADVERTISES. Also called List Price.

Discount: A reduction given on the Marked Price. Discount is always calculated on the MP — not on CP.

SP = MP × (1 − Discount%/100)

The juicy interview question combines all three: a shopkeeper marks up the price above CP, then gives a discount — and you need to figure out the final profit or loss.

Here's the mental model: Imagine a shirt costs ₹500 (CP). The shopkeeper writes ₹800 on the tag (MP — a 60% markup). Then there's a sale: 25% discount on ₹800. The customer pays ₹600 (SP). The shopkeeper still made ₹100 profit on a ₹500 shirt. He gave a discount AND still profited. That's the trick these questions test.

MarkedPriceDiscountProblem.txtINTERVIEW

=== MARKED PRICE + DISCOUNT — COMBINED PROBLEM ===

PROBLEM:
  "A shopkeeper marks a bicycle 40% above its cost
   price of ₹2,500 and then gives a discount of 20%.
   Find: (a) Marked Price  (b) Selling Price
         (c) Profit or Loss  (d) Profit/Loss %"

─────────────────────────────────────────────
Given:
  Cost Price (CP)  = ₹2,500
  Markup           = 40% above CP
  Discount         = 20% on Marked Price

Step 1 — Find Marked Price (MP):
  MP = CP × (1 + Markup%/100)
     = 2,500 × (1 + 40/100)
     = 2,500 × 1.40
     = ₹3,500

Step 2 — Find Selling Price (SP):
  SP = MP × (1 − Discount%/100)
     = 3,500 × (1 − 20/100)
     = 3,500 × 0.80
     = ₹2,800

Step 3 — Profit or Loss?
  SP (2,800) > CP (2,500)  →  PROFIT
  Profit = SP − CP = 2,800 − 2,500 = ₹300

Step 4 — Profit %:
  Profit % = (Profit / CP) × 100
           = (300 / 2,500) × 100
           = 12%

─────────────────────────────────────────────
SHORTCUT FORMULA (for combined markup + discount):

  Net % change = M − D − (M × D)/100
  where M = markup%, D = discount%

  = 40 − 20 − (40 × 20)/100
  = 40 − 20 − 800/100
  = 40 − 20 − 8
  = +12%    ← positive means PROFIT

  Same answer! Use the shortcut in exams
  when time is tight.
─────────────────────────────────────────────

Output

Marked Price = ₹3,500

Selling Price = ₹2,800

Profit = ₹300

Profit % = 12%

Shortcut result = +12% (Profit) ✓

Interview Gold:

The shortcut formula Net % = M − D − (M×D)/100 works for any combination of two successive percentage changes. Interviewers use this exact scenario to see if you know shortcuts or grind through longhand arithmetic every time.

Production Insight

Retailers use this exact markup-discount combo during clearance sales.

A 50% markup followed by 30% discount yields only 5% net profit.

Rule: always compute net % before deciding if a sale is profitable.

Key Takeaway

Discount is on Marked Price, not Cost Price.

Net % = M − D − (M×D)/100.

Calculate once, don't forget the cross term.

How to Handle Marked Price and Discount

IfGiven CP, Markup%, Discount%

→

UseFind MP = CP×(1+Markup%), then SP = MP×(1−Discount%), then profit/loss

IfGiven SP, Discount%

→

UseFind MP = SP/(1−Discount%)

IfGiven MP, Discount%

→

UseSP = MP×(1−Discount%)

Tricky Problem Types That Appear in Every Aptitude Test

Knowing the formulas is only half the battle. Aptitude tests throw a few classic curveballs that trip up even prepared candidates. Here are the three most common trap-style questions, fully worked through.

Type 1 — Two items, same SP, one profit one loss: Whenever a problem says 'two articles each sold at the same price, one at X% profit and one at X% loss' — there is ALWAYS a net loss. Always. This is a mathematical certainty.

Net Loss % = (Common %/10)² = X²/100

Type 2 — Dishonest shopkeeper using false weights: If a shopkeeper uses a 900g weight and claims it's 1000g, he's effectively gaining 100g per kg. Profit% = (True weight − False weight) / False weight × 100.

Type 3 — Successive profit/loss (buying then reselling): If you buy at CP, sell at a profit to Person B, and Person B resells at another profit, the final price chains multiplicatively — not additively.

TrickyProblemTypes.txtINTERVIEW

=== CLASSIC TRAP PROBLEMS — FULLY WORKED ===

─────────────────────────────────────────────
TRAP PROBLEM 1: Two items, same SP, X% profit & X% loss

  "Two mobiles are sold at ₹9,900 each.
   One at 10% profit, another at 10% loss.
   Is there an overall profit or loss? By how much?"

  Many people say ZERO. It's NOT zero. There is always a LOSS.

  For the item sold at 10% PROFIT:
    CP₁ = SP × 100/(100 + Profit%)
        = 9,900 × 100/110
        = ₹9,000

  For the item sold at 10% LOSS:
    CP₂ = SP × 100/(100 − Loss%)
        = 9,900 × 100/90
        = ₹11,000

  Total CP  = 9,000 + 11,000 = ₹20,000
  Total SP  = 9,900 + 9,900  = ₹19,800

  Overall   → Loss = 20,000 − 19,800 = ₹200

  Shortcut: Loss % = X²/100 = 10²/100 = 1%
  Loss amount = 1% of Total CP = 1% of 20,000 = ₹200 ✓

─────────────────────────────────────────────
TRAP PROBLEM 2: False weight shopkeeper

  "A shopkeeper uses a weight of 800g instead of
   1kg (1000g) but sells goods at the listed CP.
   What is his profit %?"

  He gives 800g but charges for 1000g.
  He gains 200g on every 800g he actually gives out.

  Profit % = (Gain / False weight) × 100
           = (200 / 800) × 100
           = 25%

  Intuition check: For every 800g he spends,
  he gets paid for 1000g — that's a 200g gain
  on an 800g investment = 25%.

─────────────────────────────────────────────
TRAP PROBLEM 3: Successive transactions

  "A buys a guitar for ₹5,000 and sells to B
   at 20% profit. B sells to C at 10% profit.
   What does C pay?"

  A's SP = B's CP = 5,000 × 1.20 = ₹6,000
  B's SP = C's CP = 6,000 × 1.10 = ₹6,600

  C pays ₹6,600.

  WRONG approach (don't do this!):
  Adding 20% + 10% = 30%  →  5,000 × 1.30 = 6,500 ✗
  Percentages in successive steps multiply, not add.

Output

Trap 1: Net LOSS of ₹200 (not zero)

Trap 2: Shopkeeper earns 25% profit using false weights

Trap 3: C pays ₹6,600 (not ₹6,500 — percentages multiply)

Watch Out:

Whenever the same percentage is used for both profit and loss on the same selling price, the result is ALWAYS a net loss — never a break-even. The loss % equals X²/100. This is a mathematical law, not a coincidence, and examiners use it to trap candidates who assume symmetry.

Production Insight

The false weight problem mirrors real fraud detection in supply chains.

If a supplier ships 950 units but charges for 1000, your profit% on cost drops.

Rule: always verify input quantity matches the invoice.

Key Takeaway

Same SP, equal profit & loss% → net loss.

False weight profit = gain over false weight.

Successive percentages multiply, don't add.

Identify the Trap Type

IfTwo items sold at same SP, one profit% one loss% (equal %)

→

UseNet loss exists; compute loss % = X²/100

IfGoods sold at CP but with false weight

→

UseProfit% = (True weight - False weight)/False weight × 100

IfMultiple successive sales with profit/loss

→

UseConvert each to multiplier and multiply; never add percentages

Tricks and Shortcuts for Timed Exams

When the clock is ticking, longhand arithmetic is your enemy. Here are the mental math shortcuts that top scorers use to solve profit and loss problems in under 30 seconds.

Shortcut 1 — Net % for Markup + Discount: Net % = M − D − (M×D)/100. If positive, profit; if negative, loss.

Shortcut 2 — Loss when same SP and equal %: Net loss % = X²/100. Plug in X, get the loss percent instantly.

Shortcut 3 — False weight profit: Profit% = (Error/False weight) × 100, where Error = True weight − False weight.

Shortcut 4 — Fraction-to-percent conversion table: Memorise common fractions: 1/2 = 50%, 1/3 ≈ 33.33%, 1/4 = 25%, 1/5 = 20%, 1/10 = 10%. Many profit% values are simple fractions of CP.

Shortcut 5 — Single discount equivalent to multiple discounts: If two successive discounts d₁% and d₂%, single discount = d₁ + d₂ − (d₁×d₂)/100.

Practice these with real numbers until they become reflex. In an exam, the difference between a good score and a great score is often just how fast you apply these.

ShortcutsSummary.txtINTERVIEW

=== SHORTCUTS REFERENCE ===

1. Net % (markup M + discount D):
   Net% = M − D − (M×D)/100

2. Net loss (same SP, equal % X profit & loss):
   Loss% = X²/100

3. False weight profit:
   Profit% = (TrueWt − FalseWt) / FalseWt × 100

4. Successive discounts d1, d2:
   Single discount% = d1 + d2 − (d1×d2)/100

5. Common fraction → profit% mapping:
   1/5 = 20%   1/4 = 25%   1/3 ≈ 33.33%
   1/2 = 50%   2/3 ≈ 66.67%   3/4 = 75%

Use these in place of full calculation when
speed is critical and numbers are round.

Output

Example: Markup 40%, Discount 20%

Net% = 40 - 20 - (40*20)/100 = 12% profit (as earlier)

Exam Strategy:

Before you start calculating, check if a shortcut applies. If numbers are round (like 20%, 25%, 10%), the shortcut likely works. Only do longhand when the numbers are irregular or when the question explicitly asks for step-by-step working.

Production Insight

In a real pricing meeting, you don't have 5 minutes per product.

Using shortcuts lets you evaluate hundreds of SKUs in minutes.

But always verify the shortcut with one sample calculation before trusting it.

Key Takeaway

Shortcuts save time but need practice.

Know when to apply each one.

Use longhand only when numbers aren't friendly.

Which Shortcut to Use?

IfMarkup + discount given

→

UseUse Net% = M − D − (M×D)/100

IfSame SP, equal profit and loss%

→

UseUse Loss% = X²/100

IfFalse weight (selling at CP)

→

UseUse Profit% = (TrueWt−FalseWt)/FalseWt × 100

IfMultiple discounts or successive transactions

→

UseConvert to multipliers and multiply

● Production incidentPOST-MORTEMseverity: high

The 1% That Cost a Retail Chain ₹2 Lakh

Symptom

End-of-month P&L showed consistent losses despite high sales volume. Inventory turnover looked healthy, but the bottom line was red.

Assumption

The store manager assumed profit% on marked price was the same as profit% on cost and that a 10% discount would reduce profit by exactly 10%.

Root cause

Profit% was calculated on SP instead of CP. This caused the discount to eat into the cost base far more than expected.

Fix

Retrain staff to use the correct formula: Profit% = (SP − CP) / CP × 100. Implement a point-of-sale check that flags when discount wipes out the cost.

Key lesson

Always anchor percentage calculations to the cost price. The base of a percentage changes everything.
When applying a discount, first compute profit on CP, then see how the discount affects SP relative to CP.
A small conceptual error can compound into a significant financial loss at scale.

Production debug guideTroubleshoot common profit/loss errors in 30 seconds3 entries

Symptom · 01

Calculated profit% doesn't match known cost or sale price

→

Fix

Check the denominator: is it CP or SP? Profit% must be (SP−CP)/CP. If you used SP, recalculate.

Symptom · 02

Net profit/loss on two items with same SP and equal % profit and loss shows break-even

→

Fix

Apply X²/100 formula: net loss is guaranteed. Calculate actual CPs separately, then total CP vs total SP.

Symptom · 03

Marked price plus discount yields unexpected profit/loss

→

Fix

Use net % formula: M − D − (M×D)/100. If result is negative, it's a loss. Verify each step with numbers.

★ Profit & Loss Calculation Error Cheat SheetQuick reference to fix the three most common calculation mistakes in aptitude tests

Profit% seems too high or low−

Immediate action

Recalculate using CP as the base

Commands

Profit% = (SP - CP) / CP × 100

Loss% = (CP - SP) / CP × 100

Fix now

If SP > CP, it's profit; if CP > SP, it's loss. Never use SP as denominator.

Successive percentages give wrong final price+

Equal SP with equal profit% and loss% seems to break even+

Profit & Loss Formulas at a Glance

Concept	Calculated On	Formula	When CP > SP or SP > CP?
Profit %	Cost Price (CP)	(Profit / CP) × 100	SP > CP
Loss %	Cost Price (CP)	(Loss / CP) × 100	CP > SP
Discount %	Marked Price (MP)	(Discount / MP) × 100	Always reduces MP
Markup %	Cost Price (CP)	((MP − CP) / CP) × 100	MP > CP always
SP from CP + Profit%	Cost Price	CP × (100 + P%) / 100	Gives SP above CP
CP from SP + Profit%	Selling Price given	SP × 100 / (100 + P%)	Reverse-engineers CP
Net % (Markup + Discount)	Cost Price	M − D − (M×D)/100	Can be + or − or 0

Key takeaways

Profit% and Loss% are ALWAYS on the Cost Price

never on Selling Price or Marked Price. This single rule eliminates the most common aptitude exam mistake.

When the same percentage applies to both profit and loss on identical selling prices, there is always a net loss of X²/100

this is a mathematical certainty, not a coincidence.

The shortcut Net % = M − D − (M×D)/100 handles any combined markup and discount in one line

learn it for timed exams where working through longhand costs you marks.

Successive percentage changes multiply, not add. Convert each percentage to a multiplier first (P% profit → ×(1 + P/100)), then chain-multiply. This works for every successive transaction problem.

Always verify your answer by working backwards. If you found CP, plug it back in to confirm the given profit% or loss%. This catches arithmetic errors in seconds.

Common mistakes to avoid

3 patterns

Calculating Profit% on Selling Price instead of Cost Price

Symptom

Your answer doesn't match any option in the MCQ, or the percentage seems too low/high.

Fix

Always anchor percentage calculations to CP. Ask yourself 'what did I originally PAY?' and use THAT number as the denominator.

Adding successive percentages instead of multiplying them

Symptom

You get an answer like 30% for a 20% then 10% chain, but the correct answer is 32%.

Fix

Convert each percentage to a multiplier (20% profit → ×1.20, 10% profit → ×1.10) and multiply the multipliers. Never add percentages across different bases.

Assuming equal SP with equal profit% and loss% means break-even

Symptom

You write 'no profit no loss' and lose the mark.

Fix

Memorise the law: same percentage profit and loss on the SAME selling price always results in a net loss of X²/100 percent. Prove it once with numbers, then never forget it.

INTERVIEW PREP · PRACTICE MODE

Interview Questions on This Topic

Q01SENIOR

A shopkeeper marks his goods 30% above cost price and offers a 10% disco...

Q02SENIOR

Two articles are sold at ₹660 each — one at a profit of 10% and one at a...

Q03SENIOR

A dishonest dealer claims to sell goods at cost price but uses a weight ...

Q01 of 03SENIOR

A shopkeeper marks his goods 30% above cost price and offers a 10% discount. Does he make a profit or loss — and by exactly what percentage? Walk me through every step.

ANSWER

Let CP = ₹100. MP = 100 × 1.30 = ₹130. SP after 10% discount = 130 × 0.90 = ₹117. Profit = SP − CP = 117 − 100 = ₹17. Profit% = 17/100 × 100 = 17%. Shortcut: Net% = 30 − 10 − (30×10)/100 = 30 − 10 − 3 = 17% profit. The shopkeeper makes a 17% profit.

FAQ · 4 QUESTIONS

Frequently Asked Questions

What is the difference between profit percentage and markup percentage?

How do I find the cost price when only the selling price and profit percentage are given?

Why is there always a loss when two items are sold at the same price — one at X% profit and one at X% loss?

Can the net % shortcut (M − D − (M×D)/100) be used for any two successive percentage changes?

🔥

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