Leslie has a set of 8 cards numbered 1 to 8. She randomly selects 2 cards one at a time WITHOUT replacement. What is the probability that she selects an odd number first and then an even number?
4/8 x 4/7= 2/7 probability of an odd then even number. 4/8 is the probability of the odd number, 4/7 is the probability of an even number after the odd card has been drawn.