Answer: Our required probability is

Explanation:
Since we have given that
P(Junior ) =

P(Senior) =

Let the given event be 'C' taking calculus.
P(C|J) = 10% = 0.10
P(C|S) = 60% = 0.60
We need to find the probability that the student is a junior.
So, our required probability is given by

Hence, our required probability is
