Mrs. Jones surveys her class about their siblings. In the class, 75% of the students have a brother, 82% have a sister, and 65% have both a brother and a sister.
What is the probability that a student has a brother or a sister?
Keep in mind, the question is asking what probability has a brother OR a sister. The 65%, that have both, does not fit the situation.
P(brother or sister) = 0.75 + 0.82  0.65 {75% have brother, 82% have sister, 65% have both which doesn't fit} = 0.92 {added and subtracted} Ask Algebra House Comments are closed.

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