Step-by-step explanation:

<h3>Answer:</h3>

The easiest way to do this is the following: if the amount increases with 7% each year, it means that you have to multiply the £400 by 1,07. Then you multiply that answer by 1,07 and one time again. The final answer is 490,0172
The tennis balls will not go the same distance
Hope this helps :D
(Sometimes i don’t know what the question is asking so pls tell me if I’m wrong)