The marked price of a revolving chair is ₹15,000. It is available on two successive discounts of 20% and 12%. What is its selling price (in ₹)?

Correct — D. Successive discounts multiply; they do not add.

After 20%: 15,000 × 0.80 = ₹12,000
After 12%: 12,000 × 0.88 = ₹10,560 → option (d)

Single-discount check: 20 + 12 − (20 × 12)/100 = 29.6%
15,000 × 0.704 = ₹10,560, the same figure.

Why the others are wrong

• (a)
  9,560 — ₹9,560 implies a discount of ₹5,440, which is 36.3% of the ₹15,000 marked price — far beyond anything 20% and 12% can strip together.
• (b)
  10,230 — ₹10,230 implies a discount of ₹4,770, or 31.8%. The two rates are worth a single 29.6%, so this cuts deeper than the offer allows.
• (c)
  9,230 — ₹9,230 implies a discount of ₹5,770, about 38.5%. The second 12% is charged on ₹12,000, not on ₹15,000, so the fall cannot grow this large.

Two successive discounts of a% and then b% leave (1 − a/100)(1 − b/100) of the marked price. Expanding that product gives the single equivalent discount:

a + b − ab/100.

For 20% and 12% that is 29.6%, always less than the 32% you get by adding the rates, because the second discount is charged on the already reduced price.

The same formula with a plus sign, a + b + ab/100, handles two successive increases.

Key facts

• 15,000 × 0.80 × 0.88 = ₹10,560.
• Two successive discounts of 20% and 12% equal a single discount of 29.6%.
• Adding the rates instead would give 32% and a selling price of ₹10,200, which is not offered.

Common traps

• Adding 20 and 12 for a 32% discount and a selling price of ₹10,200
• Charging the 12% on the ₹15,000 marked price rather than on the reduced ₹12,000

No directly related past PYQ was found.