Finding the difference between two points

Dezerai, Valentina and Xavier were walking on a track that was one mile long. Dezerai stopped at point A,

Valentina stopped at point B, and Xavier stopped at point C.

Part A: Write the fractions represented by the letters on the number line.

{_____|_______|________|________|________|______}

0 A B C 1

A = ___________

B = ___________

C = ___________

Part B: How much further did Xavier walk than Dezerai?