Mini exam 13 no 17, I think there might be more than one answer to this?

Question is this

What i did was x+2x + cx = 10 (sides of triangle)
x< cx < 3x , so cx should be 2

so now sides of triangle are 2, 4, 4

a < x < b becomes
4-4 < x < 4+4
0 < x < 8

Isnt this valid ?
Question seems kind of ambiguous to me. Am I wrong in this ?