40%
There is more than one way to figure this out. Here is one way:
(150+244+300+50) / 1240 =
744 / 1240 = .60
This means that he is spending 60% on all the things you listed above.
100 - 60 = 40
This means, that he has 40% left to spend on whatever else he wants to, thus the answer is 40%