Successive discounts of 10% and 20% are given on the purchase of a purse. If the marked price of the purse is ₹2,250, find the selling price.

Correct — D. Successive discounts compound: the second one is charged on the price the first one left, not on the marked price.

Marked price = ₹2,250
After 10%: 2,250 × 0.90 = ₹2,025

After 20% on ₹2,025: 2,025 × 0.80 = ₹1,620

In one step: 2,250 × 0.90 × 0.80 = 2,250 × 0.72 = ₹1,620
That is the amount printed in option (d)

Why the others are wrong

• (a)
  Option (a) prints ₹1,290, which implies ₹960 off ₹2,250, about 42.7%. Discounts of 10% then 20% strip exactly 28% and no more.
• (b)
  Option (b) prints ₹1,320, a discount of ₹930 or roughly 41.3%. That is far past what 0.90 × 0.80 can remove.
• (c)
  Option (c) prints ₹1,520, about 32.4% off — the nearest wrong figure. But 0.90 × 0.80 = 0.72 pins the selling price at 72% of ₹2,250, which is ₹1,620.

Two successive discounts multiply, they do not add. Keeping 90% and then 80% leaves 0.90 × 0.80 = 0.72 of the marked price.

So 10% followed by 20% is a single equivalent discount of 28%, not 30%. The missing 2% is the second discount declining to act on the part the first one already removed.

Order is irrelevant: 0.80 × 0.90 is the same 0.72, so the percentages can be printed in either sequence.

Working in multipliers rather than rupee subtractions removes the base error altogether.

Key facts

• Successive discounts of x% and y% leave (1 − x/100)(1 − y/100) of the marked price.
• Discounts of 10% and 20% together equal a single discount of 28%, not 30%.
• ₹2,250 × 0.72 = ₹1,620.

Common traps

• Adding the percentages to a flat 30% and answering ₹1,575, which is not offered.
• Charging the 20% on the marked price instead of on the reduced ₹2,025.
• Rounding ₹2,025 before applying the second discount.

No directly related past PYQ was found.