The answers to () work is not needed just answers

A)  n(a) = 25 + 15 = 40
b) n(b) = 42+15 =57
c) n (a U b) = 25 +15+ 42 = 82 
d) n (a') = 42
e) n(b') = 25
f)  n(a intersection b)' =  82-15 = 67 
g) n (a U b)' =     14 
h)  n (a'  intersection  b') =  14
i)  n (a' U b') = 42 + 25 +14 = 81 

hope i helped a bit .. :-)