Question

pritam invests Rs 20000 for two years at a certain rate of interest which amounts to Rs 22200.Find the rate of interest.

Answer 1

we know,
A =P (1+ r/100)^n
22200 =20000 (1+r/100)^2

111/100 =(1+r/100)^2

1.11= (1+r/100)^2

we know (1.1)^2 =1.21
(1.0)^2=1.00
hence 1.11 square root between 1.0 to 1.1
but it nearly 1.1 so ,
I take approx 1.06
now ,

(1.06)^2 = (1+r/100)^2
take square root
1.06 = 1+r/100
r=6% (approx )
here perfect answer only possible . when we use log table which you study in higher class .