Question

Present age of P is 15 years, and he invested Rs.4500 at 20% annual Compound Interest while Q invested Rs.5824 at 25% annual Compound Interest. When they both turn 18 years, interest amount received by both of them is same, then how old are Q at present?

• A. 14 years
• B. 16 years
• C. 17 years
• D. 12 years

Answer 1

Answer: (B)

16 years

Answer 2

The correct option is (B): 16 years.
Let at present Q is 'x' years younger to become 18 years old.
Interest amount received by P when he turns 18 years = 4500 * [(1.2)3-1] = Rs.3276
Interest amount received by Q when he turns 18 years = 5824 * [(1.25) x-1] = 3276
1.25x - 1 = $\frac{9}{16}$
1.25x = ($\frac{9}{16}$) + 1
1.25x = 1.5625 = 1.252
x = 2
Present age of Q=18-2=16 years.