Question

A and B borrowed rupees 3000 and 3500 respectively at same rate if interest for 3 years If B paid rupees 150 more interest than A find rate of interest par annum

Answer 1

Find the difference in principal:

Difference in the principle amount = 3500 - 3000 = Rs 500

Find the difference in interest received a year:

Difference in the interest received for 3 years = Rs 150

Difference in the interest received for 1 years = Rs 150 ÷ 3 = Rs 50

Find the interest rate:

Interest rate = difference in interest/ difference in principal x 100

Interest rate = 50/500 x 100 = 10%

Answer: The interest rate is 10%

Answer 2

let the rate of interest be 'r'

Sum of money borrowed by A

= ₹3000

sum of money borrowed by B

= ₹3500

let the interest paid by A be x .

given time = 3yrs , s.i = p× r × t/ 100

x = 3000 × r × 3/ 100

x = 90r => r = x / 90 ----(1)

interest paid by B

= x + 150

x + 150 = 3500 × r × 3/ 100

x + 150 = 105r

r = (x + 150)/ 105 --(2)

since , the rate of interest is same so then
equalize (1) and (2)

x/ 90 = (x + 150)/ 105

90x + 13500 = 105x

x = 900

from(1)

r = x /90 = 900/ 90 = > r = 10%

Answer: rate of interest= 10%