You want to have $35,000 in cash to buy a car 3 years from today. you expect to earn 3.6 percent, compounded annually, on your savings. how much do you need to deposit today if this is the only money you save for this purpose

The appropriate formula to use here is

A = P (1 + r)^t, 
where A is the final amount, P is the initial amount, r is the annual interest rate as a decimal fraction, and t is the number of years (number of compounding periods).

Substituting the givens:  $35000 = P(1+0.036)^3

                                   $35000
Solving for P:  P = = $31476.67    (answer)
                                (1.036)^3