Multiple choice

What is the rate of interest per annum? I. The CI in 8 years is more than the amount. II. The difference between SI and CI in 2 years is Rs.450 III. An amount double itself at SI in 15 years

  1. Only I and II are sufficient

  2. Only III is sufficient

  3. Only II and III are sufficient

  4. All are not sufficient

  5. None
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Statement III says an amount doubles itself at SI in 15 years. Using SI = (P*R*T)/100, where SI = P and T = 15, we get P = (P*R*15)/100, which simplifies to R = 100/15 = 6.66%. Thus, statement III alone is sufficient to find the rate of interest.

AI explanation

From statement III, an amount doubling itself at simple interest in 15 years means the interest earned equals the principal. Using the simple interest formula where rate equals 100 multiplied by interest divided by principal and time, the rate calculates to 100 divided by 15, making statement III alone sufficient to find the annual interest rate.

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