Answer:
3
9
21
Step-by-step explanation:
For the first one use the law of total probability
B=A∩B+A'∩B
12=9+A∩B
A∩B= 3
For this one you should use demorgans law and the union formula
(A'∩B')=(AUB)'
AUB= A+B-A∩B
6+12-3=15
15'= 24-15 = 9
For this one use demorgans law again
(A'UB')=(A∩B)'
(A∩B)'= 24-A∩B= 24-3= 21
