Length times width and that will get you an answer
Let

In order to prove this by induction, we first need to prove the base case, i.e. prove that P(1) is true:

So, the base case is ok. Now, we need to assume
and prove
.
states that

Since we're assuming
, we can substitute the sum of the first n terms with their expression:

Which terminates the proof, since we showed that

as required
Minimum is 40
First quartile is 43
Median is 61
Third quartile is 65
Maximum is 97