Question

In a college, 30 students are taking a math class and 20 students are taking an English class. 5 students are taking both English and math. How many students are taking either English or math.

Answers

bobpursley
take out those five which are taking both, and you are left with 30+20-5=45 students taking either Math or English.

P(MorE)=Pr(M)+Pr(E)-Pr(M+E)
= (30/50)+(20/50)-5/50= 45/50

so if you pick a student at random, you have a probability of .90 of getting a student who is taking Math or English, but not both.

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