This is an annuity problem. The reason is that there is a series of cash flows, in this case monthly, which need to be saved per month. You need to use the future value equation of an annuity, since the amount after a period of time (3 years) has been provided.
For the equation, please refer to the following link:
https://www.google.com/search?q=future+value+of+annuity&prmd=ivn&source=lnms&tbm=isch&sa=X&ved=0ahUKEwil1L-Uk4fQAhVCRiYKHXqxBIoQ_AUIBygB&biw=1024&bih=672#imgrc=bz4jaTWY4FeYmM%3A
You are tryng to find PMT. so PMT would be the unknown. FV has been given to you (=5000)
t=3 and m =12 (since it is monthly compound) and r = 0.09
Just plug in the values and solve for PMT and you will be done!
