Question

Given the set {A, B, C, D, E}, how many permutations and combinations are there of this set of 5 objects taken 2 at a time?

Answer 1

A 20 permutations and 5 combinations
B 10 permutations and 5 combinations
C 20 permutations and 10 combinations

Answer 2

Combinations: We want to calculate "5 Choose 2," which means taking 2 of the 5 letters at a time from the given set {A, B, C, D, E}.

The formula for 5 Choose 2 would be\[\frac{ 5! }{ 2!(5-2)! }.\] Can you evaluate this by hand or with your TI-83 or -84 calculator?

Answer 3

then what

Answer 4

wont it be A?

Answer 5

I'd hope you'd do some research on your own before asking for help.
Do you know what the factorial operator ( ! ) signifies? If so, evaluate 5!.

Answer 6

wont my answer be A?

Answer 7

Katie, I do not deal in answers alone. If you want to know how to do this problem, I'd gladly help you through it. But I'm not going to help you skip necessary work by revealing answers.

Answer 8

Do you, or do you not, know how to evaluate 5! ?

Answer 9

I dont

Answer 10

Read that "factorial 5."

Answer 11

5! ("factorial 5") is equal to 5*4*3*2*1. The ( * ) means "multiply" or multiplication.
Evaluate 5!, please.

Answer 12

what do I multply

Answer 13

5*4*3*2*1 asks you to multiply 5 by 4 (obtaining 20). Then, you multiply that 20 by the next number, which is 3. What is 20*3?

Answer 14

Later, you'll need to understand what "permutations" are. Please see the following web site:

http://www.mathsisfun.com/combinatorics/combinations-permutations.html

Answer 15

im not going to use this ever in my life