Question

In what time will rs. 1000amount to rs. 1331 at 10 %per annum compounded annually

Answer 1

principal=1000 Rs
amount=1331 Rs
so,SI= Rs(1331-1000)
=Rs331
T=SI*100/P*R
=331*100/1000*10
=3.31 yea

Answer 2

Principal = Rs. 1000
Amount = Rs. 1331
Rate = 10%
Let time is n years. Then,
C=P[(1+r)^n-1]

1331=[ 1000 (1+ (10/100))^n ] =
1331/1000=(11/10)^n
comparing both side....
1331 or (11/10)^n = (1331/1000) = (11/10)^3
n = 3 years