Question

Students in a middle school must choose to take either Band or Chorus. In a given academic year, 60% of the pupils choose Band and the rest choose Chorus. 30% of the students who are taking Band are girls, and 70% who are taking Chorus are girls. If a student is randomly selected from this academic year, what is the probability that it is a boy? A) 0.46 B) 0.49 C) 0.50 D) 0.54

Answer 1

Pupils that chose Band: 60%
Pupils that chose Chorus: 40%
Boys in band: 70%
Boys in chorus: 30%
Probability of choosing boy = Probability of boy in band + Probability of boy in chorus
P = 0.6 x 0.7 + 0.4 x 0.3
P = 0.54
The answer is D.