Multiple choice

The simple interest on a certain sum for 8 months at 4% per annum is Rs.129 less than the simple interest on the same sum for 15 months at 5% per annum. What is the sum?

  1. Rs.2580

  2. Rs.2400

  3. Rs.2529

  4. Rs.3600
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Let P be the sum. SI1 = P × 4 × 8/12 × 100 = P × 32/1200. SI2 = P × 5 × 15/12 × 100 = P × 75/1200. Given SI2 - SI1 = 129, so P × (75-32)/1200 = 129, P × 43/1200 = 129, P = 129 × 1200/43 = 3600. The difference in interest rates and time periods must be carefully accounted for.

Keep practicing — related questions