Question

Mr. Roopchand finds that an increase in the $\text{rate of interest from}4\frac{7}{8}$% $to5\frac{1}{8}\text{per\% annum}$ increases his yearly income by Rs. 25. His investment is:

• A. Rs. 10,000
• B. Rs 12,000
• C. Rs. 15,000
• D. Rs. 20,000

Answer 1

The correct option is A Rs. 10,000

Let the investement be Rs. x, then

$x\times \frac{41}{8}\times \frac{1}{100}-x\times \frac{39}{8}\times \frac{1}{100}=25$

$\Rightarrow 2x=20000\Rightarrow x=10000.$