posted by Reggie .
In a recent survey of 100 women, the following information was gathered. 38 use shampoo A. 40 use shampoo B. 50 use shampoo C. 16 use shampoos A and B. 7 use shampoos A and C. 17 use shampoos B and C. 4 use all three.
How many are using shampoos A only?
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