Answer:
11, 10
Step-by-step explanation:
n(B') = 2+5+12 = 19 ; the numbers that are not included in B
n(B∩C) = y-1 +9 = y+8 ; what belongs to both B and C
a)
n(B') = n(B∩C)
19 = y +8 ; subtract 8 from both sides
19-8 = y-8+8
11 = y
b)
n(A∪B∪C) =y -1 = 11 -1 = 10 ; is what belongs to A and B and C in the same time
