In a recent survey of 100 women, the following information was gathered.

52 use shampoo A.
31 use shampoo B.
39 use shampoo C.
11 use shampoos A and B.
13 use shampoos A and C.
15 use shampoos B and C.
10 use all three.


How many are using shampoo A only? ___
Using the Venn diagram, I got 35 but it was wrong.

I get 38

Of the 52 A's, 10 use ABC 3 use AC 1 uses AB