So a free body diagram might look like this:

Newtons second law say F = ma or, in this case ∑F_{y} = ma_{y}

The sum of the forces in the y direction is: F_{air resistance} + F_{g} and that equals ma_{y}

We also know that F_{g} = mg

So F_{air resistance} + mg = ma_{y} or F_{air resistance} = ma_{y} - mg

We know a_{y} = -3.2 m/s^{2}, we know g = -9.81 m/s^{2}, we know m = 80 kg

So:

F_{air resistance} = ma_{y} - mg

F_{air resistance} = 80(-3.2) - (80)(-9.8)

F_{air resistance} = -256 - (-784) = -256 + 784 = 528 (this answer is in Newtons but you are told to just give a number answer without units)