Question

Denny chose two cards randomly from a deck of cards numbered 1-10.

What is the probability of getting a 9 and then a 6 without replacing the
cards?

Answer 1

1/90

Explanation:

Let's start by listing out the cards.

1 2 3 4 5 6 7 8 9 10

There are 10 options. Each card has an equal chance of getting chosen. Therefore, the probability of selecting one specific card, 9, is 1/10.

The 9 is not replaced. Let's now list the new cards.

1 2 3 4 5 6 7 8 10

There are 9 options. Each card has an equal chance of getting chosen. Therefore, the probability of selecting one specific card, 6, is 1/9.

P(A and B) = P(A) * P(B). Taking the first event as event A and the second as event B (order doesn't matter here), we have (1/10) * (1/9) = 1/90