Question

At RC Edwards Middle School, the probability that a student takes Technology and Spanish is 0.087. The probability that a student takes Technology is 0.68. What is the probability that a student takes Spanish given that the student is taking Technology?

Answer 1

Define
P(S) = probability that the student takes Spanish.
P(T) = probability that the student takes Technology
          (= 0.68).
P(T and S) = probability that the student takes Technology and Spanish
                     (= 0.087).
P(S|T) = probability that the student takes Spanish, given that the student takes Technology.

The Law of Conditional Probability is
P(T and S) = P(S|T)*P(T)

Therefore
0.087 = P(S|T)*0.68
P(S|T) = 0.087/0.68 = 0.128

Answer: P(S|T) = 0.128