There are four cards in a box, each with a different number written on it -- either 1, 3, 4 or 5. What is the probability that the difference between the numbers on two randomly selected cards is not greater than 3?
There are four cards in a box, each with a different number written on it -- either 1, 3, 4 or 5. What is the probability that the difference between the numbers on two randomly selected cards is not greater than 3?