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?
1, 2, 3, 4, 5, 6, 7, 8
Probability of picking an odd number is: 4/8==1/2
probability of the 2nd number being even is: 4/7
Then, the probability of picking an odd number followed by an even number is: 1/2 x 4/7 ==4/14 ==2/7