“Ascending Order”: Is it possible to solve this using the FCP rule?

Question

Is it possible to solve this using the FCP rule?

Answer

Yes, it's possible to use the Fundamental Counting Principle here:

The probability = (number of ways that satisfy condition) / (total number of ways)

The numerator is just 1; there is only one way to choose the four numbers in ascending order: 1, 2, 3, 4

We use the FCP to find the denominator, the total number of ways. We have 4 choices for the first number, 3 for the second, 2 for the third, 1 for the last:

So our total ways is 4 * 3 * 2 *1 = 24

So our probability is 1/24

Link

http://gre.magoosh.com/questions/857