Towns X, Y, and Z are on the same straight road. Town Y is between Town X and Town Z. Town X is 57 miles from Town Z, and Town Y is 28 miles from Town Z.
Total distance=57 miles.
Subtract the distance from y to z
57 miles - 28 miles = 29 miles
Hence,
The distance from Town X to Town Y is 29 miles.
I hope it helps.
Thank you