The simple interest on Rs 1800 for 4 years is Rs 20 more than the simple interest on Rs 1700 for 4 years at the same rate. What is the rate of interest per annum?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 5%
With the same rate and time, the extra interest is the simple interest on the extra principal of \(1800-1700=\) Rs 100.
\(\displaystyle \frac{100\times R\times4}{100}=20\)
\(4R=20\), so \(R=5\)
The rate of interest is 5% per annum.