Calculate in how many years will Rs. 300000 amount to Rs. 399300 at the rate of 10% compound interest per annum.

Explanation

here principal `=Rs. 300000`
Rate of compound interest `=10%` per annum let the required time be `t` years.
`:.` The amount of Rs. 300000 after `t` years `=Rs. 300000xx(1+10/100)^(t)`
`=Rs. 300000xx(1+1/10)^(t)`
`=Rs. 300000xx(11/10)^(t)`
As per questinon `300000xx(11/10)^(t)=399300`
or `(11/10)^(t)=399300/30000`
`=1331/1000=(11/10)^(3)`
`:.(11/10)^(t)=(11/10)^(3)impliest=3`
Hence the required time `=3` years.