Question

Instructor A of statistics passes 90% of his students. Instructor F passes 60% of his students. A student picks a teacher at random. What is the probability that he passes statistics?

Answer 1

The probability that he passes statistics is `75%`

Explanation:

As the student picks a teacher at random, the probability of picking either teacher is `1/2`.

As such the probability of picking Instructor A and passing statistics is `1/2xx90%=45%`.

and the probability of picking Instructor B and passing statistics is `1/2xx60%=30%`.

Hence, the probability that he passes statistics is `45%+30%=75%`