Finite math help

Question

Solve the following problem.

PV=$19,810​;

n=117​;

i=0.03​;

PMT=?​;

Answer 1

If you pay P each month, the present value is Prn, where r = 1/(1+i), and the sum is Pr(1 - rn)/(1-r)

Note that r/(1-r) = 1/(1+i)/(1 - 1/(1+i)) = 1/i

Thus, the sum is P(1 - (1/1+i)n)/i

Then, if our value is the Principal, P = Principal(i)/(1 - (1/1+i)n)

Then, P = $19,810 * .03/(1 - (1/1.03)117) = $613.61712324

PMT is the last figure , PMT =$613.61712324