math
posted by khushboo .
A high school guidance counselor conducts a survey to find the student's first choice for a college major and found that 65% of students choose math. If three students are chosen at a random, what is the probability that at least one of them would choose math?

prob(choose math) = .65
prob(not to choose math) = .35
prob(at least 1 of 3 choosing math)
= 1  prob(nobody choosing math)
= 1  C(3,0) (.35)^3
= 1  .042875
= appr .957
or
prob(1 choosing math) + prob(2 choosing math) + prob(3 choosing math)
= .957