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there are 7 bags and 7 balls out of which
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09 Mar 2020, 03:26
09 Mar 2020, 03:26
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Question Stats:
78% (01:27) correct
21% (01:43) wrong based on 14 sessions
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there are 7 bags and 7 balls out of which 3 balls are identical. In how many ways can these 7 balls be put inside the 7 bags, such that no bag is left empty?
A)420
B)600
C)840
D)900
E)1140
How to solve this?
A)420
B)600
C)840
D)900
E)1140
How to solve this?
Re: there are 7 bags and 7 balls out of which
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13 Mar 2020, 13:48
13 Mar 2020, 13:48
2
Since 3 balls are identical, their order in the bags doesn't matter. Thus, we only need to find all the possible combinations of bags for the 4 distinct balls. This can be done by selecting 4 bags out of 7 (\(7C4\)) and then shuffling the order of the 4 distinct balls (\(4!\)).
Hence, the final answer is \(7C4 * 4! = 840\)
Hence, the final answer is \(7C4 * 4! = 840\)
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Re: there are 7 bags and 7 balls out of which
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01 Feb 2021, 07:43
01 Feb 2021, 07:43
1
There are 7 bags and 7 balls of which 3 are identical, then these can be arranged in 7! / 3! ways = 840 ways
