The numbers 1, 2, 3, 4, and 5 are written on slips of paper and two are drawn at random without replacement. What is the probability that the sum is 5 or less?

Answer 1

Universal Set

U = {(1,2), (1,3), (1,4), (1,5), (2,1), (2,3), (2,4), (2,5), (3,1), (3,2), (3,4), (3,5), (4,1), (4,2), (4,3), (4,5)}

Set of sum≤5

S = {(1,2), (1,3), (1,4), (2,1), (2,3), (3,1), (3,2), (4,1)}

Since 8 out of 16 possible combinations have sums of less than 5, then there's an 8/16 = 1/2 = 50% chance of selecting two number slips with a sum of 5 or less without replacement.

Hope this helped!