Probability of Compound Events

A total of 50 students play either soccer or lacrosse.

• 20 girls play lacrosse
• 20 boys play either soccer or lacrosse
• 20 students play soccer

What is the probability that a student plays soccer or is a girl.

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There are 30 girls and 20 boys.

Find the probability of a student playing soccer
= 20/50 = 0.4

Find the probability that a student is a girl
= 30/50 = 0.6

Find the probability that a student plays soccer and is a girl
= 10/50 = 0.2

Find the probability that a student plays soccer or is a girl
P = 0.4 + 0.6 - 0.2
= 0.8

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