Answer:
16
Step-by-step explanation:
9/12=12/x
x=16
S = n(a1 + an)/2
2S = n(a1 + an)
2S = na1 + nan
nan = 2S - na1
an = (2S - n a1)/n
A = {1, 3, 5, 7, 9} B = {2, 4, 6, 8, 10} C = {1, 5, 6, 7, 9} A ∩ (B ∪ C) =
vovikov84 [41]
A = {1, 3, 5, 7, 9}
B = {2, 4, 6, 8, 10}
C = {1, 5, 6, 7, 9}
(B ∪ C) = {1, 2, 4, 5, 6, 7, 8, 9, 10}
so
A ∩ (B ∪ C) = {1, 5, 7 , 9}
The total will be $19.72 with 20% so she will get back $30.28