The formula that you want for this one is actually
PMT = [P * r/n] / [1 – (1 + r/n)^(-nt)]
So it’s just a matter of using the information given in the question in order to find what those values would be and then simplify algebraically
On this one we have
P = $112,000 – 0.20($112,000) = $89,600 because the down payment is not going to be in the loan amount
r = 0.115/year
n = 12 months/year
t = 30 years
Putting that all together would be
PMT = [$89,600 * 0.115/12] / [1 – (1 + 0.115/12)^(-12*30)]
PMT = $885.93
That means that the required monthly payment here would be $885.93. I hope that helps :)
