Find the answer to the below problem
- Sage BLv 41 decade ago
P stands for permutation. You have seven items; you are only taking two of them. Permutation means that order matters. For instance, if you have seven people and you are going to draw two names: the first name drawn will get a $1000 scholarship and the second name drawn will get a $500 scholarship, you can see that order is important!
What you are finding is the total number of possible outcomes.
Formula: n factorial over (n minus r) factorial
n! over (n - r)!
n is the number to the left of the P and r is the number to the right. n can NEVER be larger than (but can be equal to) r.
Factorial means to multiply from the stated number all the way down to one.
This is what you have:
7! over (7 - 2)!
7! over 5!
7*6*5*4*3*2*1 over 5*4*3*2*1
Hopefully, you will see that the fives cancel, the fours cancel, the threes cancel, the twos cancel, and the ones cancel. That leaves you with 7 * 6 which is 42.
There are 42 distinct ways to pull out two items from seven where order matters!!!