Question

If a sum of money at simple interest doubles itself in 6 years, it will become four times in

• A. 14 years
• B. 12 years
• C. 18 years
• D. 16 years

Answer 1

The correct option is C 18 years

Let sum$=x$

We know,

$S.I.=\frac{PRT}{100}$

SI$=x$

Rate$=\frac{(100\times x)}{(x\times 6)}$

$=\frac{50}{3}\%$

Now sum $=x$, S.I$=3x$

Rate$=\frac{50}{3}\%$

Time

$=\frac{(100\times 3x)}{x\times \frac{50}{3}}$

$=18$ years.