What percent of the class could be the suspect?

Question

In a class of 30 students, 8 were wearing a white t-shirt. In the same class, 14 students had on blue jeans. Eyewitnesses stated that the suspect was dressed in a white shirt and jeans. What percent of the class could be the suspect?

Answer 1

Use a venn diagram

X is the number of students wearing

white t-shirt and blue jeans...

8-x is the number of students wearing

white t-shirt but NOT blue jeans

14-x is the number of students wearing

blue jeans but NOT white t-shirt

y is the number of students wearing

NEITHER white t-shirt , NOR blue jeans

8-x +x + 14-x + y = 30

22 - x + y = 30

y - x = 8

y = x+8

x y=x+8 8-x 14-x percent

0 8 8 14 0.000%

1 9 7 13 3.333%

2 10 6 12 6.667%

3 11 5 11 10.000%

4 12 4 10 13.333%

5 13 3 9 16.667%

6 14 2 8 20.000%

7 15 1 7 23.333%

8 16 0 6 26.667%