Question

Of the 400 freshmen at Westview High School, 92 students are in band, 60 students are in chorus, and 20 students are in both band and chorus. If a student is chosen at random, Find each probability as a fraction (in simplest form), decimal, and percent.

question .1 student in chorus and in band
question 2 student (not in band | in chorus)
question 3 student (in band | not in chorus)

Answer 1

1-P(Band and Chorus) = 20/400 = 1/20 = 0.05 = 5%
2-P(Not in Band | In Chorus) = 40/60 = 2/3 = 0.6667 = 66.67%
3-P(In Band | Not in Chorus) = 72/340 = 18/85 ≈ 0.2118 ≈ 21.18%