Multiple choice

Find the minimum number of years for which simple interest must be reckoned at 5% p.a. on Rs. 512.50 so that the interest may be an exact number in rupees.

  1. 4 years

  2. 8 years

  3. 6 years

  4. 10 years
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Interest = (P * R * T) / 100 = (512.50 * 5 * T) / 100 = (512.5 * T) / 20 = 25.625 * T. For this to be an integer, T must be a multiple of 8 (since 25.625 = 205/8).

AI explanation

Using the simple interest formula, the interest is 512.50 times 5 times the number of years divided by 100, which equals 2562.5 times the years divided by 100, or 2065 divided by 8 times the years. For the interest to be an exact whole number of rupees, the number of years must make the fraction a whole number. The minimum number of years to cancel the denominator 8 is 8.

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