Question

What is the least possible number which must be subtracted from 17, 23, and 33 so that the resulting numbers are in mean proportion?

• A. 6
• B. 7
• C. 8
• D. 9

Answer 1

The correct option is C 8

Let x be the least number subtracted.

$\frac{(17-x)}{(23-x)}=\frac{(23-x)}{33-x}$

⇒ (17 – x)(33 – x) = (23 – x)²

⇒ 17 × 33 – 17x – 33x + x² = 23² + x² – 46x

⇒ 561 – 50x = 529 – 46x

⇒ 32 = 4x

⇒ x = 8.

Alternately, we can solve the question from the options.

Hence, option C is the correct answer.