Multiple choice

Zenil invested a sum of money at a certain rate of simple interest for a period of 4 years. Had he invested the same sum for a period of 6 years the total interest earned by him would have been 50 per cent more than the earlier interest amount. What was the rate of interest per cent per annum?

  1. 2 years

  2. 4 years

  3. 8 years

  4. Data insufficient
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Simple interest I = P*R*T/100. Interest for 4 years = P*R*4/100. Interest for 6 years = P*R*6/100. The problem states 6-year interest is 50% more than 4-year interest. (P*R*6/100) = 1.5 * (P*R*4/100). This simplifies to 6 = 6, which is always true regardless of R. Thus, R cannot be determined.

AI explanation

The simple interest formula is SI = (P * R * T) / 100. Let the initial interest for 4 years be I, meaning the new interest for 6 years is 1.5I. Because interest is directly proportional to time, the ratio of time is 4 to 6, which already equals the ratio of interest, making the equation independent of the rate R. The principal and rate cancel out perfectly, meaning the rate of interest cannot be calculated from the given information. The data provided is insufficient to answer the question.

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