Question

What is the rate of interest p.c.p.a.?
I. An amount doubles itself in $5$ years on simple interest.
II. Difference between the compound interest and the simple interest earned on a certain amount in $2$ years is $Rs.400$.
III. Simple interest earned per annum is $Rs.2000$.

• A. I only
• B. II and III only
• C. All I, II and III
• D. Any two of the three
• E. I only of II and II only

Answer 1

Answer: (E)

I only of II and II only

I. $\frac{P\times R\times 5}{100}=P\Rightarrow R=20$.
II. $P{(1+\frac{R}{100})}^2-P-\frac{P\times R\times 2}{100}=400\Rightarrow P{R}^2=4000000$.
III. $\frac{P\times R\times 1}{100}=2000\Rightarrow PR=200000$.
$\therefore \frac{P{R}^2}{PR}=\frac{4000000}{200000}\Rightarrow R=20$.
Thus I only or (II and III) give answer.
$\therefore$ Correct answer is (E).