Step-by-step explanation:
........................
Answer: The answer is 120
Step-by-step explanation: you add 50+70 and u will get 120
To solve this problem you must apply the proccedure shown below:
1. You must apply the following formula:

Where
is the future value,
is the present value,
is the interest rate and
is the time in years.
2. You have that the bank will double your money in
years. Therefore:

3. Substitute values into the formula and solve for
, as following:

4. By applying natural logarithm, you have:

%
The answer is:
%
6 because if thet are doing it togather jhon will speed things up