English

A boy has 3 library tickets and 8 books of his interest in the library. Of these 8, he does not want to borrow Mathematics Part II, unless Mathematics Part I is also borrowed. In how many ways can h

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Question

A boy has 3 library tickets and 8 books of his interest in the library. Of these 8, he does not want to borrow Mathematics Part II, unless Mathematics Part I is also borrowed. In how many ways can he choose the three books to be borrowed?

Sum
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Solution

Let us make the following cases:

Case (i): Boy borrows Mathematics Part II

Then he borrows Mathematics Part I also.

So the number of possible choices is 6C1 = 6.

Case (ii): Boy does not borrow Mathematics Part II

Then the number of possible choices is 7C3 = 35.

Hence, the total number of possible choices is 35 + 6 = 41.

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Chapter 7: Permutations and Combinations - Solved Examples [Page 119]

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NCERT Exemplar Mathematics [English] Class 11
Chapter 7 Permutations and Combinations
Solved Examples | Q 11 | Page 119

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