SOLUTION: a computer with an old processor locks up if more then 4 applications are running simultaneously.If the ower has 20 application stored in his program file,how many different sets o

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Question 352991: a computer with an old processor locks up if more then 4 applications are running simultaneously.If the ower has 20 application stored in his program file,how many different sets of 4 can he run,so that his computer does not lock up?
Answer by sudhanshu_kmr(1152) About Me  (Show Source):
You can put this solution on YOUR website!

For first set 4 applications can be selected from 20 by 20C4 ways

For second set 4 applications can be selected from 16 by 16C4 ways

For third set 4 applications can be selected from 12 by 12C4 ways

For fourth set 4 applications can be selected from 8 by 8C4 ways

For fifth set 4 applications can be selected from 4 by 4C4 ways




Hence total no. of ways = 20C4 * 16C4 * 12C4 * 8C4 * 4C4

= 20! / (4^5)