Arun borrowed a sum of money from Jayant at the rate of 8\% per annum simple interest for the first four years, 10\% per annum for the next 6 years and 12\% per annum for the period beyond 10 years. If he pays a total of ₹ 12160 as interest only at the end of 15 years, how much money did be borrow?
(a)₹ 8000
(b)₹ 9000
(c)₹ 10000
(d)₹ 12000
Answer
Answer (as printed): A
Explanation
Let the sum be ₹ $x$. Then, $\left(\frac{x \times 8 \times 4}{100}\right)+\left(\frac{x \times 10 \times 6}{100}\right)+\left(\frac{x \times 12 \times 5}{100}\right)=12160$ $\Rightarrow 32 x+60 x+60 x=1216000$ $\Rightarrow \quad 152 x=1216000 \Rightarrow x=8000$.
Explanation as extracted from the printed page; notation may be imperfect.