Respuesta :

In general, nCr = n! / r! (n-r)!

Here, 7C3 = 7! / 3!(7-3)!

=7 x 6 x 5 x 4 x 3 x 2 x 1 /3 x 2 x 1 ( 4 x 3 x 2 x 1)

=7x6x5x4 / 4x3x2

=7x5x6x4 / 24

=35x24 / 24

=35

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