ABC26GN4177 · Compound Interest
Subject: General Aptitude · Chapter: Compound Interest · Exam: · Marks: · Difficulty:
The difference between compound interest and simple interest on a sum for 2 years at 8 per cent is ₹ 768. The sum is
(a)₹ 100000
(b)₹ 110000
(c)₹ 120000
(d)₹ 170000
Answer
Explanation
Let the sum be ₹ $x$. Then, $$\begin{aligned} & \text { C.I. }=₹\left[x\left(1+\frac{8}{100}\right)^{2}-x\right] \\ & =₹\left(\frac{729}{625} x-x\right)=₹\left(\frac{104 x}{625}\right) . \\ & \text { S.I. }=₹\left(\frac{x \times 8 \times 2}{100}\right)=₹\left(\frac{4 x}{25}\right) . \\ & \therefore \frac{104 x}{625}-\frac{4 x}{25}=768 \\ & \Rightarrow \frac{4 x}{625}=768 \\ & \Rightarrow x=\left(\frac{768 \times 625}{4}\right)=120000 . \end{aligned}$$
Explanation as extracted from the printed page; notation may be imperfect.
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