Question

a certain sum of money amounts yo $1344 in 3 years and $1440 in 5 years.find the sum and rate of interest.

Answer 1

let assume initial amount is x and rate of interest is r.

after 3 year amount will be= x*(1+r)^3=1344

after 5 years amount will be=x*(1+r)^5=1440

so, 1440=x*(1+r)^3 *(1+x)^2=1344*(1+r)^2

(1+r)^2= 1440/1344=1.0743

1+r = 1.035

rate of interest is = 3.5%

x* (1.035)^3=1344

x*1.1087=1344

x=1344/1.1087=1212.230

sum is 1212.230

rate of interest = 3.5%