If the specific rotation of Compound X is (-) 123.8º, what would be the observed

rotation of its enantiomer, Compound Y, assuming the concentration and cell path length
is the same?
b. If a racemic mixture of Compound X and Compound Y were analyzed, what would be
the observed rotation?
c. What would be the specific rotation of Compound Z, a diastereomer of Compound X
and Y?

3 answers

a. +123.8
b. 0
c. http://en.wikipedia.org/wiki/Diastereomer
After reading the link for part c,i still don't understand it
would it be that Z is -123.8 since X is -123.8 and Y is +123.8?