Question 864622: how many different ways are there for the group to record a CD consisting of 12 songs chosen from 25 new songs? use permutations or combinations (the order of the songs is relevant )
Answer by jim_thompson5910(35256)   (Show Source):
You can put this solution on YOUR website! Order is important, so we use a permutation.
P(n,r) = (n!)/((n-r)!)
P(25,12) = (25!)/((25-12)!)
P(25,12) = (25!)/(13!)
P(25,12) = (25*24*23*22*21*20*19*18*17*16*15*14*13!)/(13!)
P(25,12) = 25*24*23*22*21*20*19*18*17*16*15*14
P(25,12) = 2,490,952,020,480,000
The answer is 2,490,952,020,480,000 which is the number 2 quadrillion 490 trillion 952 billion 20 million 480 thousand (definitely a big number). A shorter way to say it is to round to the nearest trillion to get 2.491 quadrillion.
The answer in scientific notation is 2.49095202048 * 10^15 and that can be shortened to 2.491 * 10^15
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