Question

if the amount is 119790 and principal is 90000 and rate is 10% compounded annually find its time period

Answer 1

Given,
Principal P =Rs 90,000
Amount A = Rs 1,19,790
Rate r = 10% compounded annually
Time period n = ?
By applying formula,
A = $P(1 - r/100)^n$
=> 119790 =$90000(1 +10/100)^n$
=> 119790/90000 = $(1+1/10)^n$
=>1331/1000 = $([10+1]/10)^n$
=> 1331/1000 = $(11/10)^n$
=> (11/10)^3 = $(11/10)^n$
Since bases are same, exponents have to be same,
n=3
Time period for the Principal of Rs 90000 to become Amount Rs 119790 is 3 years. (Ans)