A student is taking 2 courses. .62 chance of passing 1st course and .62 chance of passing the 2nd.

there is a .79 chance she passes at least 1 class.
what is the probability she passes exactly 1 course? (to 4 decimals)
given she passes the first, what is the probability she passes the second?(to 4 decimals)
given she passes the 1st, what is the probability she does not pass the second?(to 4 decimals)

P(A or B) = P(A) + P(B) - P(A & B)
0.79 = 0.62 + 0.62 - P(A & B) , so P(A & B) = 0.45

(a) P(pass exactly 1 course) = P(A or B) - P(A & B) = 0.79 - 0.45 = 0.3400 <------

(b) P(A & B) / P(A) = 0.45/0.62 = 0.7258 <--------

(c) P(B') = 1-0.62 = 0.38 , P(A & B') = P(A only) = 0.62- 0.45 = 0.17
P(A & B') / P(A) = 0.17/0.62 = 0.2742 <---------

draw a venn diagram for clearer understanding