Question

Use the Rule of 72 to solve. Manny has his money in a savings account earning 4.5% interest. How long it will take his money to double? sixteen years twelve years two years eighteen years

Answer 1

Explanation:

72 divided by 4.5 equals 16

Answer 2

It will take 15.76 year to double the amount

Explanation:

We have given rate of interest r = 4.5 %

Let the principle amount is P

It is given that amount is doubled so amount A = 2P

Amount is given by
`A=P(1+(r)/(100))^n`, her n is time period

So
`2A=A(1+(4.5)/(100))^n`

`1.045^n=2`

Taking log both side

`nlog1.045=log2`

`n* 0.0191=0.3010`

[tex]n=15.8year[/text]

It will take 15.76 year to double the amount