Question

Mahesh borrowed a certain sum for 2 years at simple interest from bhim . mahesh lent this sum to vishnu at the same rate for two years ,at the end of 2 years 'mahesh received 410 as compound interest but paid 400 as simple interest. find the sum and rate of interest

Answer 1

Answer: Sum = 4000, Rate of interest = 5%.

Step-by-step explanation:

We know that SI = PTR/100

                        P = SI * 100/r*t

                           = 400 * 100 / r * 2

                           = 20000/R  ------------------ (1)

We know that CI = P(1+r/100)^n - P

 

                           = P(1+r/100)^n - 1

                    410 = 20000/R(1+r/100)^n - 1

                    410 = 20000/R(10000 + R^2 + 2000R - 10000)/10000

                    410 = 2/R(R^2 + 200R)

                    410R = 2(R^2+200R)

                    2R^2 + 400R - 410R = 0

                    2R^2 = 10R

                       R = 5.

Substitute R in (1), we get

P = 20000/5

  = 4000.

Sum = 4000, Rate of interest = 5%.

Hope this helps!