CK-12-Basic Probability and Statistics Concepts - A Full Course

http://www.ck12.org Chapter 2. Conditional Probability

Therefore, 10 P 2 =90, which means that the number of ways that first and second place can be awarded to 10 people
is 90.

Example C

In how many ways can 3 favorite desserts be listed in order from a menu of 10? Compute the answer using your TI
calculator.

There are 10 menu items(n= 10 ), and you are choosing 3 favorite desserts(r= 3 )in order, so to find the answer,
enter the following into your TI calculator:

10 MATH I I I (PRB) 2 (nPr) 3 ENTER

After pressing

ENTER

, you should see the following on your calculator’s screen:

Therefore, 10 P 3 =720, which means that the number of ways that 3 favorite desserts can be listed in order from a
menu of 10 is 720.

Guided Practice

Verify that thenProption on the PRB menu of the TI calculator works by calculating 18 P 18 with both this option
and with the factorial function. Note that with the TI calculator, you can find the factorial function by pressing

MATH

, pressing the right arrow 3 times, and pressing

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