Math
posted by Ms Jackie .
In a recent survey of 100 women, the following information was gathered.
42 use shampoo A.
38 use shampoo B.
34 use shampoo C.
7 use shampoos A and B.
9 use shampoos A and C.
11 use shampoos B and C.
5 use all three.
How many are using shampoos A and C, but not B?
_____women

9 use shampoos A and C. This set of 9 also includes people who would use B.
5 people use all three
9  5 = 4