A certain sum of money becomes Rs 1000 in 2 years and Rs 1100 in 4 years at a simple rate of interest. The rate of interest per annum is

A4 and 3 by 7 percent

B5 and 5 by 9 percent ✓ Correct

C7 and 4 by 7 percent

D6 and 4 by 9 percent

Correct answer: (B) 5 and 5 by 9 percent

Explanation

The rate is 5 and 5/9 percent per annum.

Interest from year 2 to year 4 = 1100 - 1000 = 100 for 2 years.

So yearly interest = 50, and 2-year interest = 100.

Principal = 1000 - 100 = 900.

Rate = (50/900) x 100 = 50/9 = 5 and 5/9 percent.

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