$45.00. The best way to work problems like this is in reverse, and then checking your work by working them forward. In reverse:

X - 1/3X = 15

2/3X = 15

2X = 45

X = 22.5

Then:

2X = 22.5

X = 11.25

And finally:

X - 3/4X = 11.25

1/4X = 11.25

X = 45

Winner: FSteenberg