Solve the problem.
-Seven slips of paper marked with the numbers 1, 2, 3, 4, 5, 6, and 7 are placed in a box and mixed well. Two are drawn. What are the odds that the sum of the numbers on the two selected slips is not 5?
A)9 : 1
B)21 : 2
C)19 :1
D)19 :2

Question

Quizplus · Accepted Answer

The total number of ways to draw 2 slips out of 7 is C(7,2) = 21. The combinations that sum to 5 are (1,4) and (2,3), which are 2 in total. Therefore, the number of draws that do not sum to 5 is 21 - 2 = 19. The odds in favor of not summing to 5 are 19 to 2.

Solve the Problem. -Seven Slips of Paper Marked with the Numbers 1, 2