You have 4 reindeer, Bloopin, Balthazar, Gloopin, and Prancer, and you want to have 3 fly your sleigh. You always have your reindeer fly in a single-file line. How many different ways can you arrange your reindeer?

Question

Mathematics

Chaya Rodriguez

2 June, 15:51

You have 4 reindeer, Bloopin, Balthazar, Gloopin, and Prancer, and you want to have 3 fly your sleigh. You always have your reindeer fly in a single-file line. How many different ways can you arrange your reindeer?

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Answers (1)

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Ernest Pham · Answer 1

P43=4! (4-3) !=241=24

Step-by-step explanation:

There are four choices you can make for the lead reindeer. For each possible choice, there are then three remaining you can choose to fly second, making 4*3=12 choices for the lead pair. For each possible choice there are two remaining reindeer to take up the back position, making 12*2=24 choices for the team of three.

This type of problem is called a permutation problem, and we write Pnr for the number of ways of choosing r items from n possibilities when the order of the items matters. In this case we are choosing 3 reindeer from 4 possibilities, and the order they appear in the flying line does matter, so the answer we want is P43. The general formula is Pnr=n! (n-r) !. For the answer we are looking for we therefore have:

P43=4! (4-3) !=241=24