You have 4 reindeer, prancer, rudy, jebediah, and bloopin, 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?

Alright, so there are 4 reindeer to fill 3 different positions, which is a permutation. If you have a calculator, this can be calculated by finding the nPr function and filling in 4P3 (4 pick 3).

If you don't have a calculator, you can use the formula:
n! / ((n-r)!)
where n is the total number in the set and r is the number chosen

solving that formula:
4! / (4-3)! = 4*3*2*1/1 = 24

Either way, you get the answer of 24.

You can use a calculater and divide the minutes by the $$, hope that you