Question 324338
P(freshman)=(10+15)/(10+15+20+5)=25/50=1/2
P(female)=(15+5)/50=20/50
P(freshman and female)=15/50
Subtract those that are freshman and female so they're not double counted.
P(freshman or female)=P(freshman)+P(female)-P(freshman and female)
P(freshman or female)=25/50+20/50-15/50
P(freshman or female)=30/50=3/5
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Another way to look at it is "find the probability of selecting a freshman or a female sophomore",
P=25/50+5/50=30/50=3/5