Question

A sum of money triples itself in 15 years 6 months. In how many years would it double itself?

• A. 6 years 3 months
• B. 7 years 9 months
• C. 8 years 3 months
• D. 9 years 6 months

Answer 1

The correct option is B 7 years 9 months

Let sum = x,

Then, S.I. = 2x & Time 31/2 years.

$Rate=(\frac{100\times 2x}{x}\times \frac{2}{31})\%=\left(\frac{430}{31}\right)\%$

Now, sum = x. S.I. = x& Rate
$\left(\frac{400}{31}\right)\%$

$\therefore Time=(\frac{100\times x}{x}\times \frac{31}{400})years$

= 7 years 9 months