Rate of Interest (r)=20% Amount (A) =2× Principal (P) Formula used: A=P(1+r∕100)t Calculation: 2P=P(1+20∕100)t ⇒2=(1+0.2)t ⇒2=(1.2)t Now, we calculate t for different values: For t=2,(1.2)2=1.44 For t=3,(1.2)3=1.728 For t=4,(1.2)4=2.0736 ⇒ At t=4, the amount exceeds double the principal.
