I am studying for the p exam and realized I really need to brush up on my basic set theory, and am having trouble with this question.

In a survey on Popsicle flavor preferences of kids aged 3-5, it was found that:

- 22 like strawberry.

- 25 like blueberry.

- 39 like grape.

- 9 like blueberry and strawberry.

- 17 like strawberry and grape.

- 20 like blueberry and grape.

- 6 like all flavors.

- 4 like none.

Apparently the answer is 50, but I can't seem to figure out how to arrive at this

In a survey on Popsicle flavor preferences of kids aged 3-5, it was found that:

- 22 like strawberry.

- 25 like blueberry.

- 39 like grape.

- 9 like blueberry and strawberry.

- 17 like strawberry and grape.

- 20 like blueberry and grape.

- 6 like all flavors.

- 4 like none.

Apparently the answer is 50, but I can't seem to figure out how to arrive at this