I had ₹ 10000 with me. Out of this money I lent some money to A for 2 years @ 15\% simple interest. I lent the remaining money to B for an equal number of years @ 18\% simple interest. After 2 years, I found that A had given me ₹ 360 more as interest as compared to B. The amount of money which I had lent to B must have been
(a)₹ 2000
(b)₹ 3000
(c)₹ 4000
(d)₹ 5000
Answer
Answer (as printed): C
Explanation
Let the sum lent to A be ₹ $x$ and that lent to $B$ be ₹ $(10000-x)$. Then, $$\frac{x \times 15 \times 2}{100}-\frac{(10000-x) \times 18 \times 2}{100}=360$$ $\Rightarrow 30 x-360000+36 x=36000 \Rightarrow 66 x=396000$ $\Rightarrow \quad x=6000$. Hence, sum lent to $\mathrm{B}=₹(10000-6000)=₹ 4000$.
Explanation as extracted from the printed page; notation may be imperfect.