If a certain sum of money at Simple interest doubles itself in 5 years, then what is the rate?
5%
20%
25%
14.8%
Explanation:
Let the principal be 100.
Then, Amount = 200, SI=100
SI=p $\times$ n $\times$ r/100.
=> r=100 $\times$ si/p $\times$ n.
=> r=100 $\times$ 100/100 $\times$ 5.
=> r=20.