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Taking 2 at a time from 4 different objects, how many combinations are there?
AFour combinations
BSix combinations
CEight combinations
DNine combinations
Answer & Solution
Correct answer: B. Six combinations
1. The pairs are AB, AC, AD, BC, BD and CD.
2. BA, CA, DA, CB, DB and DC are not listed because order does not alter a combination.
3. Counting the distinct pairs gives 6.
_Source: NCERT Class 11 Mathematics, Ch 6 'Permutations and Combinations'_
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