A shopkeeper, on the eve of Diwali, allowed a series of discounts on television sets. Find the selling price of a television set, if the marked price of television is ₹1,200 and successive discounts are 15% and 10%.

Correct — C. Successive discounts multiply, they never add.

Marked price = ₹1,200
After the 15% discount: 1200 × 0.85 = ₹1,020
After the 10% discount on ₹1,020: 1020 × 0.90 = ₹918

Net multiplier = 0.85 × 0.90 = 0.765, an equivalent single discount of 23.5%, not 25% → option (c).

Why the others are wrong

• (a)
  ₹945 — ₹945 leaves ₹255 off the ₹1,200 tag — a single discount of 21.25%. Discounts of 15% and then 10% strip 23.5% of the tag, which is ₹282.
• (b)
  ₹975 — ₹975 is 81.25% of the marked price, an 18.75% cut. Neither discount alone nor the two together produce that fraction.
• (d)
  ₹965 — Order does not matter here — 0.90 × 0.85 is the same 0.765 as 0.85 × 0.90 — so no sequencing of the two discounts reaches ₹965. Both routes land on ₹918.

A discount is a multiplier on the marked price, not a subtraction you can pool.

A discount of d% leaves (1 − d/100) of the price standing, so two discounts applied one after the other leave the product of the two survivors: 0.85 × 0.90 = 0.765.

That is why 15% and 10% together strip 23.5% and not 25% — the second discount is charged on a price the first has already shrunk. The shortcut a + b − ab/100 says the same thing: 15 + 10 − 1.5 = 23.5.

Key facts

• Selling price after successive discounts = Marked price × (1 − d₁/100) × (1 − d₂/100).
• Two successive discounts of a% and b% equal one discount of (a + b − ab/100)%, here 23.5%.
• 1,200 × 0.85 = 1,020 and 1,020 × 0.90 = 918.
• Successive discounts commute: taking the 10% first and the 15% second also gives ₹918.

Common traps

• Adding the discounts to 25% and answering ₹900
• Charging the second 10% on the ₹1,200 marked price instead of on ₹1,020

No directly related past PYQ was found.