In Triangle ABC, Angle B = 15 degrees less than twice angle A and Angle C is more than angle A. Find angle C.

B=2A-15

C>A
and A+B+C=180
which becomes...
A+(2A-15)+C=180
C=180+15-3A
C=165-3A

so

Which sets our boundary to test for valid triangles. After trial and error (there's probably a better way) we can deduce the following.
The least value for C under these conditions is C=42 and the greatest is a little more than 142
so...these are pretty good approximations