Question

Find the effective rate of interest if payments of 300 at the present, 200 at the end of one year, and 100 at the end of two years accumulate to 800 at the end of three years.

Answer 1

Answer:

12.93%

Explanation:

Given that the amount of 300 is invested for 3 years, while the amount of 100 is invested for 2 years and 100 is invested for 1 year.

also amount accumulated in three years = 800

Applying the formula to find the future value we get

300(1+r)^3 + 200(1+r)^2 + 100(1+r) = 800

which can be further simplified to

300r^3+1100r^2+1400r+600=800

where, r is the effective rate of interest which we have to find out

The above equation is cubic in r, so to solve this we can use equation solver. When we put this equation in equation solver we get

r = 0.12926

r ≅ 0.1293

Therefore,  effective rate of interest  = 12.93%