From Bayes Theorem, P(A|B) = P(B|A)*P(A)/P(B)
If A is team winning and B is MJ playing, then
P(B|A) is the probability of winning when MJ is playing = 75%
P(A) is the probability of winning in general = 60%
P(B) is the probability of MJ playing in the game which is not given.
We need to find P(B). MJ plays in 75% of the wins (60%) and 35% of the losses (40%). 75% x 60% + 35% x 40% = 59%
Back to the formula, Probability of winning given MJ is playing is 75% x 60% / 59% = 0.76