Profit Loss Master - Quick Revision

Profit Loss Master – Quick Revision

One-Liners

  1. CP = Cost at which article is bought.
  2. SP = Price at which article is sold.
  3. Profit = SP – CP (only when SP > CP).
  4. Loss = CP – SP (only when CP > SP).
  5. Profit % = (Profit / CP) × 100.
  6. Loss % = (Loss / CP) × 100.
  7. Discount is always calculated on Marked Price (MP).
  8. If two articles sold at same price, one at p% profit & other at p% loss, net loss = (p² / 100) %.
  9. When CP of x = SP of y, Profit % = [(x – y)/y] × 100.
  10. If profit is p%, SP = CP × (100 + p)/100.
  11. If loss is l%, SP = CP × (100 – l)/100.
  12. To get x% profit on SP, CP = SP × 100 / (100 + x).
  13. Successive discounts a% & b% give equivalent discount = [a + b – (ab/100)] %.
  14. False weight: Gain % = (Excess / True weight) × 100.
  15. Article sold at 1/n of CP ⇒ Loss % = [1 – 1/n] × 100.
  16. Article sold at 2 times CP ⇒ Profit % = 100 %.
  17. Mark-up above CP x%, then max discount d% allowed without loss: d ≤ [100x/(100 + x)] %.
  18. Overall profit/loss on two transactions = combine absolute profits/losses, never average percentages.
  19. Always take CP as 100 % base to avoid fraction errors.
  20. Break-even ⇒ SP = CP ⇒ Zero profit, zero loss.

Formulas / Rules

Formula Use
Profit % = (SP – CP)/CP × 100 Convert profit to percentage
Loss % = (CP – SP)/CP × 100 Convert loss to percentage
SP = CP × (100 ± g)/100 Find selling price for gain/loss g%
CP = SP × 100 / (100 ± g) Find cost price given SP & g%
Equivalent Discount = d₁ + d₂ – d₁d₂/100 Combine two successive discounts
Marked Price = CP × (100 + m)/100 When mark-up m% is on CP
Gain by false weight = (Excess / True) × 100 Dealer gives less weight
Net effect of equal % profit & loss on same CP = (p²/100)% loss Two separate sales, same CP
Overall Profit/Loss % = (Total Profit or Loss / Total CP) × 100 Multiple items, one transaction
If x goods bought for 1 rupee & sold y goods for 1 rupee, Profit % = [(x – y)/y] × 100 Special rate-based profit

Memory Tricks

  1. SPicy Formula: SP = CP × (100 ± P%) → “Spice it up for profit, spice it down for loss.”
  2. Discount Dance: Equivalent discount always “add then subtract product-over-hundred.”
  3. Same-Price-Same-Percent: Same CP, same % gain & loss → remember “square-the-percent-loss”.
  4. False Weight Fear: Gain% = (cheated / true) × 100 → “Cheated on weight, cheated on profit.”
  5. CP-is-King: Every percentage is calculated ON CP – say “C-for-Centre, C-for-CP.”

Common Errors

Error Correct
Taking SP as base for profit % Always use CP as base
Adding discounts directly (20% + 10% = 30%) Use formula d₁+d₂–d₁d₂/100 = 28%
Averaging profit & loss % for net effect Compute absolute profit/loss first, then % on total CP
Using MP instead of CP for profit % Profit is on CP, discount is on MP
Forgetting to convert % to decimal in SP/CP formulas Divide percentage by 100 before substitution

5 Quick MCQs

Question 1 A trader marks his goods 40 % above CP and gives a discount of 20 %. What is the profit %?
A) 12 % B) 15 % C) 20 % D) 8 %
AnswerA) 12 %
Question 2 By selling 8 pens a man gains cost price of 2 pens. His gain % is
A) 20 % B) 25 % C) 30 % D) 15 %
AnswerB) 25 %
Question 3 A machine is sold at a loss of 10 %. Had it been sold for ₹ 90 more, there would have been a gain of 5 %. The CP is
A) ₹ 500 B) ₹ 600 C) ₹ 800 D) ₹ 900
AnswerB) ₹ 600
Question 4 Two articles are sold at ₹ 1,000 each, one at 25 % profit and the other at 25 % loss. Net result is
A) No loss no gain B) 6.25 % loss C) 6.25 % gain D) 5 % loss
AnswerB) 6.25 % loss
Question 5 A dealer uses 900 g instead of 1 kg. His gain % is
A) 10 % B) 11.11 % C) 12.5 % D) 9.09 %
AnswerB) 11.11 %