Suppose That $| A | = | B | = | C | = 100 , | A \cap B | = 60 , | A \cap C | = 50 , | B \cap C | = 40 , \text { and } | A \cup B \cup C | = 175$

Suppose that $| A | = | B | = | C | = 100 , | A \cap B | = 60 , | A \cap C | = 50 , | B \cap C | = 40 , \text { and } | A \cup B \cup C | = 175$
How many elements are in $A \cap B \cap C ?$