A bag contains the numbers 1 through 20 inclusive. If three are selected at random and placed in order from smallest to largest, find the probability that the arrangement is of three consecutive integers.

Printable View

- Nov 1st 2006, 04:17 AMpunmasterProbability
A bag contains the numbers 1 through 20 inclusive. If three are selected at random and placed in order from smallest to largest, find the probability that the arrangement is of three consecutive integers.

- Nov 1st 2006, 12:25 PMearboth
- Nov 1st 2006, 12:42 PMThePerfectHacker
Here is another way.

---

Probability is favorable to possible.

What is favorable?

{1,2,3} All premutations of this set = 6

{2,3,4} All premutations of this set = 6

.....

{18,19,20} All premutations of this set = 6

In total we have,

18 Sets

Thus,

The possible outcomes is the number of ways of selecting 3 out of twenty.

Which is,

Thus,

- Nov 1st 2006, 01:04 PMPlato
- Nov 1st 2006, 01:07 PMThePerfectHacker