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Number of ways in which three numbers in...

Number of ways in which three numbers in AP can be selected from 1,2,3, . .,n is

A

`((n-2)(n-4))/(4)`, if n is even

B

`(n^(2)-4n+5)/(2)`, if n is odd

C

`((n-1)^(2))/(4), ` if n is odd

D

`(n(n-2))/(4)`, if n is even

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The correct Answer is:
C, D
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