In a survey of 100 women,

34 use shampoo A
42 use shampoo B
31 use shampoo C
9 use shampoo A&B
10 use shampoo A&C
6 use shampoo B&C
2 use all three

How many use shampoo A & C, but not B?

10 use A&C (may or may not use B)

2 use all three (A, B & C)
So how many use A & C but not B?

To find the number of people who use shampoo A & C but not B, we need to subtract the number of people who use all three (A, B, and C) from the number of people who use shampoo A & C.

From the given information:
- 34 use shampoo A
- 31 use shampoo C
- 10 use shampoo A & C
- 2 use all three (A, B, and C)

To find the number of people who use shampoo A & C but not B, we can follow these steps:

Step 1: Find the number of people who use shampoo A, C, and B:
Since 2 people use all three (A, B, and C), subtracting this number from the total number of people who use shampoo A & C will give us the number of people who use A & C but not B:

10 (use shampoo A & C) - 2 (use all three) = 8

Therefore, 8 people use shampoo A & C but not B.