Question

A sum of money at simple interest becomes 1.5 times of itself in 3 years. In how many years will the same treble itself?

• A. 10 years
• B. 11 years
• C. 12 years
• D. 13 years

Answer 1

Answer: (C)

12 years

Let sum of money $=P$ and Rate be $P$.

For Part 1

$A=1.5P$

$T=3$

$A=P(1+\frac{RT}{100})$

$\Rightarrow 1.5P=P(1+\frac{3R}{100})$

$\Rightarrow 0.5=\frac{3R}{100}$

$\Rightarrow R=\frac{100\times 0.5}{3}=\frac{50}{3}$

For Second Part

$A=3P$

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

$Time=T$

ATP, $3P=P(1+\frac{50T}{3\times 100})$

$\Rightarrow 3=1+\frac{50T}{300}$

$\Rightarrow 2=\frac{T}{6}$

$\Rightarrow T=12$

Hence, Time required $=12$ years.