Question

A sum of money becomes $\frac{41}{40}$ of itself in $\frac{1}{4}$ years at a certain rate of simple interest. What is the rate of interest per annum

• A. $8\%$ per annum
  
• B. $10\%$ per annum
  
• C. $12\%$ per annum
  
• D. $14\%$ per annum
  

Answer 1

Answer: (B)

$10\%$ per annum

Let P = Rs $x$. Then,

A = Rs $\frac{41}{40}x,$

Simple Interest $\left(SI\right)=A-P$ = $\frac{41}{40}x-x$$=\frac{x}{40}$

$T=\frac{1}{4}$ year.

Hence $R$ = $\frac{S.I.\times 100}{P\times T}$

$=\frac{\frac{x}{40}\times 100}{x\times \frac{1}{4}}$

$=\frac{100\times 4}{40}$ = 10% p.a.