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Profit, Loss & Discount Β· Topic 3 of 8

πŸ”» Successive Discounts

2 exam question types, fully solved

Two discounts one after another are never their sum β€” the second comes off the already-reduced price, so the real discount is always less than a + b.

The single equivalent discount

Two discounts a% and b% equal a single discount of a + b βˆ’ %. So 20% and 10% give 30 βˆ’ 2 = 28%, never 30%.

β€’ Or multiply the surviving fractions: is the part still paid; 1 minus it is the discount.

β€’ For three discounts, combine two into one equivalent, then combine with the third β€” or chain the fractions once: 25%, 20% and 10% leave paid, a single 46% discount (tag β‚Ή600 β†’ pay β‚Ή324).

β€’ β€œBuy n, get m free” is a discount of : buy 3 get 1 free β†’ = 25% off, never 33%.

Slabs & conditions: for β€œX% off above β‚ΉN”, use only the single highest slab reached β€” they don't stack. And β€œ>β‚ΉN” excludes the exact value β‚ΉN.

🏷️Discount CalculatorDiscount is on MP
first discount %
second discount %
Single equivalent = a + b βˆ’ ab/100 = 20 + 10 βˆ’ (20Γ—10)/100
= 28% off (not 30%)

Discounts of 20% and 10% equal a single discount of 30 βˆ’ 2 = %.

πŸ“Practice Questions

Q1Two successive discounts of 10% and 20% equal a single discount of:

Q2On MP β‚Ή500, discounts of 20% then 10% give SP:

Q3Two equal discounts giving a single 19% discount means each is:

πŸ“š

Real exam questions β€” Successive Discounts

2 question types Β· 6 solved examples from real SSC papers

Two discounts in a row are never their sum β€” the second comes off the reduced price. Use the single equivalent.

How to solve this type
Two successive discounts of a% and b% are never a+b. The fast way: a single equivalent discount of a+bβˆ’ab100a+b-\dfrac{ab}{100} %. Equivalently, multiply the two surviving fractions 100βˆ’a100Γ—100βˆ’b100\dfrac{100-a}{100}\times\dfrac{100-b}{100} β€” that gives the fraction of the price the customer still pays, and 1 minus it is the discount. For three discounts, combine the first two into one equivalent, then combine that with the third. To find an original/marked price, multiply all the surviving fractions and divide the amount paid by that product. Because the answer is always below a+b, you can instantly reject any option β‰₯ a+b.

Two successive discounts of 20% and 10% are equal to a single discount of:

A28%B29%C30%D32%

A shirt has 25% off, plus 20% for cash, plus 10% for a loyal customer. She paid β‚Ή324. The price tag was (in β‚Ή):

A600B650C725D750

On a bill, the difference between a single 27% discount and two successive discounts of 20% and 10% was β‚Ή56. The bill amount was:

Aβ‚Ή1,120Bβ‚Ή1,866Cβ‚Ή5,500Dβ‚Ή5,600