This item is a probability problem.
The question that is asked is that "What is the Probability of being left-handed given that you put on your left shoe, first?"
P (left-shoe) = 20 / 150
P (right-shoe) = 93 / 150
P (right | left-shoe) = 10 / 20
P (left | left-shoe) = 10 / 20
P (right | right-shoe) = 90 / 93
P (left | right-shoe) = 3 / 93
P ( left-handed | left-shoe ) = 10 / 20
