If 1 × 2 × 3 × ...... × n is denoted by n! ,then (8!

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If 1 × 2 × 3 × ...... × n is denoted by n! ,then (8! – 7! – 6!) is equal to :

1. 6 × 8 × 6!
2. 7 × 8 × 6!
3. 6 × 7 × 8!
4. 7 × 8 × 7!

Correct Option: A

As we now that , n! = 1 × 2 × 3 × .........× n
∴ 8! - 7! -6! = (8 × 7 × 6!)– (7 × 6!) – 6!
Required answer = 56 . 6! – 7 . 6! – 6!
Required answer = (56 – 7 – 1) 6!
Hence , Required answer = 48 . 6! = 6 × 8 × 6!