Question

At what rate percent annum will a sum of money double itself in 5 years?

Answer 1

Answer:

rule 72

Step-by-step explanation:

hope you get ....

Answer 2

Answer:

The rough guess would be using the 72 rule, i.e., divide 72 by either the time or the interest rate to get the one or the other.

In this case, we divide 72 by 5 to get 14.4 as the needed interest rate.

We can check this by:

(1+r)^5=2

Then take the log of each side:

log (1+r)^5=log 2

5 log (1+r)=0.30103

log (1+r)=0.060206

Then:

10^log (1+r)=10^0.060206

1+r=1.148698355

r=14.8698355% √ …