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?

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

P(brother or sister) = 0.75 + 0.82 - 0.65 {75% have brother, 82% have sister, 65% have both which doesn't fit}

=

**a sister. The 65%, that have both, does not fit the situation.**__OR__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__