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