Question

Granny puts $35,000 into a bank account earning 4%. You can't withdraw the money until the balance has doubled. How long will you have to leave the money in the account

Answer 1

It will take 17 years and 245 days.

Step-by-step explanation:

Giving the following information:

Granny puts $35,000 into a bank account earning 4%. You can't withdraw the money until the balance has doubled.

We need to find the number of years required to achieve $70,000.

We will use a variation of the final value formula:

FV= PV*(1+i)^n

Isolating n:

n=[ln(FV/PV)]/ln(1+r)

n= [ln(70,000/35,000)] / ln(1.04)= 17.67

To be more accurate:

0.67*365= 245 days

It will take 17 years and 245 days.