Question

# From a collection of 20 consecutive natural numbers, four are selected such that they are not consecutive. The number of such selections is 284×17285×17284×16285×16

Solution

## The correct option is A 284×171,2,3,4,.....,20 There are 17 way for four consecutive number. Number of selections = 20C4–17                                    =285×17–17                                    =284×17

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