SOLUTION: What is the formula for this problem: A class contains 10 students enrolled in JAVA and 20 students in C++. Half of the students in JAVA and half of the students in C++ are enro

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Question 611983: What is the formula for this problem:
A class contains 10 students enrolled in JAVA and 20 students in C++. Half of the students in JAVA and half of the students in C++ are enrolled in Statistics. Find the probability that a student chosen at random is enrolled in C++ or enrolled in Statistics.
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I have tried solving this by using the Addition Rule in statistics,
20/30 + 15/30 - 10/30 = 25/30
Is this correct?

Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!


Yes, that is right, but there is a simpler way to get the answer. Look at the complement of your successful outcome. If your successful outcome is C++ or Statistics, then the complement is neither C++ nor Statistics. The only group that fits the complement set is the half of the Java students who are NOT taking Stat. That is 5/30 and 1 - 5/30 = 25/30. N'est-ce pas?

John

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