Arun invested a sum of money at a certain rate of simple interest for a period…
2025
Arun invested a sum of money at a certain rate of simple interest for a period of four years. Had he invested the same sum for a period of six years the total interest earned by him would have been fifty percent more than the earlier interest amount. What was the rate of interest per cent per annum?
- A.
4
- B.
8
- C.
5
- D.
Cannot be determined
Attempted by 22 students.
Show answer & explanation
Correct answer: D
Key idea: Substitute the simple interest formulas and simplify.
Let the principal be P and the rate be R% per annum.
Simple interest for 4 years = 4PR/100. Simple interest for 6 years = 6PR/100.
Given that interest for 6 years is 50% more than interest for 4 years: 6PR/100 = 1.5 × (4PR/100).
Cancel the common factor PR/100 from both sides to get 6 = 1.5 × 4 = 6, which is an identity independent of R.
Since R cancels out, the rate cannot be uniquely determined from the given information.
Answer: Cannot be determined.