Question

Out of a sum of Rs 3,200 a part was spent at 6% simple interest and the other at 9% simple interest. If the interest on the first part after 3 years is equal to the interest on the second part after 6 years, then what is the second part?

• A. Rs 600
• B. Rs 700
• C. Rs 800
• D. Rs 900

Answer 1

Answer: (C)

Rs 800

Let the second part be $Rs.x$. Then first part is $Rs.(3200-x)$

So interest on first part $=\frac{(3200-x)\times 6\times 3}{100}=\frac{18(3200-x)}{100}$

And interest on second part $=\frac{\left(x\right)\times 9\times 6}{100}=\frac{54\left(x\right)}{100}$

Now, according to question:

$\frac{18(3200-x)}{100}=\frac{54x}{100}$

$\Rightarrow 54x+18x=18\times 3200$

$\Rightarrow 72x=57600$

$\Rightarrow x=800$

Hence the second part is $Rs.800$.