# SOLUTION: Please help me solve this one. I guess this is a combination problem but I can't figure out my n and r. Thanks a lot! Seven identical balls are randomly placed in seven availabl

Algebra ->  Algebra  -> Permutations -> SOLUTION: Please help me solve this one. I guess this is a combination problem but I can't figure out my n and r. Thanks a lot! Seven identical balls are randomly placed in seven availabl      Log On

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 Algebra: Combinatorics and Permutations Solvers Lessons Answers archive Quiz In Depth

 Question 48187: Please help me solve this one. I guess this is a combination problem but I can't figure out my n and r. Thanks a lot! Seven identical balls are randomly placed in seven available containers in such a way that two balls are in one container. Of the remaining six containers, each receives at most one ball. Find the number of ways in which this can be accomplished.Answer by stanbon(57222)   (Show Source): You can put this solution on YOUR website!Seven identical balls are randomly placed in seven available containers in such a way that two balls are in one container. Of the remaining six containers, each receives at most one ball. Find the number of ways in which this can be accomplished. 1st: Pick a container to contain 2 balls: 7 ways 2nd: Select two balls to put in that container: 1 way as the balls are identical 3rd: Pick a container to be empty: 6 ways 4th: Put a ball in each of the remaining five containers: 1 way as the balls are identical. # of ways is 7*6 = 42 Cheers, Stan H.