Question

A pack of cards consists of 9 cards numbered 1 to 9

Answer 1

Here is the complete question:

From a pack of 9 cards numbered 1-9, three cards are drawn at random and laid on a table from left to right. What is the probability that the digits are drawn in descending order?

Answer:

If we look at this question we really don't need the information regarding the number of the cards in the pack. We just need distinct numbers.

So when we will draw 3 cards regardless of the fact which cards are these, they will be 3 distinct numbers and they will be in the descending order.

Our equation to the total number of different possible orders of the 3 cards will look like this:

3! = 3 . 2 . 1 = 6

For the first card we need the 3 choices for the second we need 2 and 1 for the third.

In this case the probability of the cards in the descending order will be:

1/3! = 1/6

1/6 is the answer