Question

Out of a sum of $Rs.640$, a part was lent 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. $Rs.120$
• B. $Rs.140$
• C. $Rs.160$
• D. $Rs.180$

Answer 1

The correct option is C $Rs.160$

Let the two parts be x and y
$\Rightarrow \frac{x\times 6\times 3}{100}=\frac{y\times 9\times 6}{100}$
$\Rightarrow \frac{x}{y}=\frac{3}{1}$ or $x:y=3:1$
Dividing $640$ in $3:1$, second part $=\frac{1}{4}\times Rs.640=160$.