मराठी

Find the number of ways of selecting 9 balls from 6 red balls, 5 white balls and 5 blue balls if each selection consists of 3 balls of each colour. - Mathematics

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प्रश्न

Find the number of ways of selecting 9 balls from 6 red balls, 5 white balls and 5 blue balls if each selection consists of 3 balls of each colour.

बेरीज
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उत्तर

There are a total of 6 red balls, 5 white balls, and 5 blue balls.

9 balls have to be selected in such a way that each selection consists of 3 balls of each colour.

Here,

3 balls can be selected from 6 red balls in 6C3 ways.

3 balls can be selected from 5 white balls in 5C3 ways.

3 balls can be selected from 5 blue balls in 5C3 ways.

Thus, by multiplication principle, required number of ways of selecting 9 balls

= 6Cx 5Cx 5C3 = `(6!)/(3!3!) xx (5!)/(3!2!) xx (5!)/(3!2!)`

= `(6 xx 5 xx 4 xx 3!)/(3! xx 3 xx 2) xx (5 xx 4 xx 3!)/(3! xx 2 xx 1) xx (5 xx 4 xx 3!)/ (3! xx 2 xx 1`

= 20 x 10 x 10

= 2000

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पाठ 7: Permutations and Combinations - Exercise 7.4 [पृष्ठ १५३]

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एनसीईआरटी Mathematics [English] Class 11
पाठ 7 Permutations and Combinations
Exercise 7.4 | Q 5 | पृष्ठ १५३

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