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 .. :-)