1)

A certain sum of money becomes three times of itself in 20 Yrs at simple interest. In how many years does it become double of itself at the same rate of simple interest?


A) 8 Yrs

B) 10 Yrs

C) 12 Yrs

D) 14 Yrs

E) None

Answer:

Option B

Explanation:

Case I

$P=x$; $A=3x$; $I=2x$

$SI$ $=\frac{PNR}{100}$  $\Rightarrow 2x$ $=\frac{(x\times R\times 20)}{100}$

$R$ $=10\%$

Case II

$P=x$; $A=2x$ ; $I=x$; $N$ = ?

$SI$ $=\frac{PNR}{100}$ $\Rightarrow x=\frac{(x\times N\times 10)}{100}$

$N$ = 10 Yrs