How many numbers must be selected from the set {1, 2, 3, 4} to guarantee that at least one pair of these numbers add up to 7?
A. 14
B. 5
C. 9
D. 24
Answer:B
How many numbers must be selected from the set {1, 2, 3, 4} to guarantee that at least one pair of these numbers add up to 7?
A. 14
 B. 5
 C. 9
 D. 24
