Question

if a sum of 40000 at compound interest at 5%p.a. amounted to 44100 find the time for which money was invented.

Answer 1

P(1+ r/100)^t = Amount

40000(1+ 5/100)^t= 44100

(105/100)^t= 44100/40000

(21/20)^t= 441/400

(2 1/20)^t= (21/20)^2

t=2
so the money was invested for 2 years.
$2$