Since the budget is 4500 dollars per month, and every month is made of 4 weeks, the weekly budget is
[tex] \dfrac{4500}{4} = 1125\$ [/tex]
We know that Mr Gleason takes home 900$ per week, so he almost make the whole budget: there are only [tex] 1125 - 900 = 225 \$ [/tex] left.
If Mrs Gleason brings home 9 dollars per hour, she'll have to work
[tex] \dfrac{225}{9} = 25 [/tex] hours per week.