Ms. Nelson will receive $15,000 a year for the next 20 years from her retirement fund. If a 7.5% percent interest rate is applied, what is the current value of her retirement?

I have this formula in excel, but I am not getting the answer my professor gave us:

=PV(0.075,20,-15000,0,0) this is my formula and I get $152,917.37

But he says the answer is $186,933.16

Could you please tell me what am I doing wrong?

thank you