A) See the attached graph. The purple area appears to be what you want to find.
b) Integrating with respect to x seems much easier. If one were to integrate over y, there would need to be two regions of integration: [1, e^2] and [e^2, e^4].
Jorge would have $8.25 left. This answer does not include 9 cups + the $1.75 it said he bought in the beginning. I’m pretty sure the 9 is the total amount of cups he bought. If it isn’t then subtract another $1.75 and you should get $6.50