Compute the total amount repaid on a mortgage for $70,000 at 9% for 35 years.9% @ 35/year = 7.84

This problem can be solved by simple economics. Since compounding interest is not specified, let's keep it simple and just deal with simple interest. The equation to use is:

F = P(1+rn)
where
F is future worth
P is present worth
r is interest rate
n is time

F = (70,000)(1+0.09*35)
F = $290,500

Iam thinking the answer is a.) knew