Use the Combinations Formula
-A stack of 9 different cards are shuffled and spread out face down. If 4 cards are turned face up, how many different 4-card combinations are possible?
A) 126
B) 3024
C) 15,120
D) 1512

Question

Quizplus · Accepted Answer

The number of different 4-card combinations possible from a stack of 9 different cards is calculated using the combinations formula, which is $C(n, k) = \frac{n!}{k!(n-k)!}$, where $n$ is the total number of items, and $k$ is the number of items to choose. Here, $n=9$ and $k=4$, so $C(9, 4) = \frac{9!}{4!(9-4)!} = \frac{9!}{4!5!} = 126$.