JEE MATHEMATICS MCQ: PERMUTATIONS

1 Easy

1 of 1

Application +4 | -1

The number of mappings (functions) from the set

A = \left\{ {1,\;2,\;3} \right\}

into the set

B = \left\{ {1,\;2,\;3,\;4,\;5,\;6,\;7} \right\}

such that

f\left( i \right) \le f\left( j \right)

whenever

i < j

, is

View answer and explanation

Correct option: A

Option A (84) is correct because it represents the number of non-decreasing functions from A to B, calculated by stars and bars method or combinations with repetition.

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