Algebra question help please

Question

Joshua put $50 per month in an investment plan that pays an APR of 4.5%. How much money will he has after 18 years? Compare this amount to the total deposits made over the time period. 

Answer 1

FV = PMT((1 + i)^nt - 1)/i = 50((1 + 0.045/12)^12·18 - 1)/(0.045/12) = $16593.40 ; ˜

Interst: 16593.40 - 50·12·18 = $16593.40 - $10800 = $5793.40