The marked price of a piano was ₹ 15,000. At the time

The marked price of a piano was ₹ 15,000. At the time of sale, there were successive discounts of 20%, 10% and 10% respectively on it. The sale price was

1. ₹ 9,720
2. ₹ 9,750
3. ₹ 9,760
4. ₹ 9,780

Correct Option: A

Use the below formula to calculate the Equivalent single discount.

Equivalent single discount =		D₁ + D₂ −	D₁ × D₂		%
			100

Single equivalent discount for 20% and 10% =		20 + 10 −	20 × 10		% = (30 - 2) = 28%
			100

Single equivalent discount for 28% and 10% =		28 + 10 −	28 × 10		% = ( 38 - 2.8 ) % = 35.2%
			100

∴ S.P. of Piano =	15000 ×(100 −35.2)
	100

∴ S.P. of Piano = ₹ 9,720
Alternate method to solve this question :
According to given question.
Here, M.P. = ₹ 15000 , S.P. = ?
D₁ =20%, D₂ = 10%, D₃ = 10%

S.P = M.P		100 − D₁			100 − D₂			100 − D₃
		100			100			100

⇒ S.P = 15000		100 − 20			100 − 10			100 − 10
		100			100			100

⇒ S.P = 15000 ×	80	×	90	×	90
	100		100		100

⇒ S.P = 15 × 72 × 9 = ₹ 9720

Discount

Aptitude

Correct Option: A