Answer:
15 X w(how many weeks) + 30 = 90 or 15 X 4 + 30 = 90
Explanation:
so he needs $90 he has $30 and he gets 15 a week so we are going to say a week will be w so however many weeks (4) so you will need to multiply it by 15 and it will be 60 then you add 30 and you get 90.