Hints

1. Calculate the interest rate

• You are expected to return a percentage.

2. Calculate the interest

• When calculating interest, it might be helpful to notice that interest_rate returns a percentage.
• You can use the function defined in the previous task (interest_rate) to calculate the interest.

3. Calculate the annual balance update

• When calculating the annual balance update, use the functions that have been defined in the previous steps.

4. Calculate the years before reaching the desired balance

• To calculate the years, one can keep looping until the desired balance is reached using a for loop.
• There is a special operator to increment values by 1.