Tony is 24 miles from the house.
Jake is 10 miles from the house.
They are 26 miles apart.
Looks like you have most of the details already, but you're missing one crucial piece.
is parameterized by

for
and
, and a normal vector to this surface is

with norm

So the integral of
is

25----------5 and 5--------------5 and 1 ------------5 and 1
What i can see the total amount is wrong
Answer:
(Q) Find the amount in the account at the end of 1 year.
(A) $8,190
2.
(Q) Find the amount in the account at the end of 2 years.
(A) $16,380