Question

5. A sum of money lent out at simple interest amounts to
6,200 in 1 year and to 6,800 in 3 years. Find the
sum and the rate of interest.​

Answer 1

Amount ( A ) = ₹ 6200

Time ( T ) = 1 year

In 3 years , the added amount = ₹ 6800 - ₹ 6200

===> ₹ 600

The interest in 2 years is ₹ 600

In 1 year = ₹ 600 / 2 = ₹ 300

Interest per annum = ₹ 300

P = A - I

[ P = Principal , A = Amount & I = Interest ]

P = ₹ 6200 - ₹ 300 = ₹ 5900

The sum is ₹ 5900

R = I × 100 / PT

R = 300 × 100 / 5900 × 1

R = 30,000 / 5900

R = 5.08 per annum

Rate of interest = 5.08 %