If maxine spent 15 hours of home work last week and 18 hours of homework this week she says she spent 120% this week doing homework is she right?

Wrong because you can't spend more than 100% if a week doing something

Like the answer below, you can't spend more thatn 100% which is what you have

the question is worded badly
read it
if maxine spent 15 hours last week ant 18 hours this week, she spent 120% of this week doing homework

I would guess we shoudl compare the increase
if the question is like, this week is 120% of last week, the answer would be correct
because
18=120% of 15
18=1.2*15
18=18
true

but, if you only red the question, then
each week=7 days, 24 hours, 7*24=168
15/168=9%
18/168=11%
not even close to 120%

I would say that the time she spent this week was 120% of the time last week