Resolved: "How do you evaluate 7C2 ?"

Helen Lewis

Answered question

2021-12-19

How do you evaluate

7 C_{2}

Carl Swisher

Beginner2021-12-20Added 28 answers

Explanation:

n C r = (\begin{matrix} n \\ r \end{matrix}) = \frac{n!}{r! (n - r)!}

n C r = (\begin{matrix} 7 \\ 2 \end{matrix}) = \frac{7!}{2! (7 - 2)!} = \frac{7!}{2! \cdot 5!} = \frac{5040}{2 \cdot 120} = \frac{5040}{2040} = 21

Charles Benedict

Beginner2021-12-21Added 32 answers

Evaluate

7 C_{2}

using the formula

n C_{r} = \frac{n!}{r! (n - r)!}

\frac{7!}{2! (7 - 2)!}

Subtract 2 from 7.

\frac{7!}{2! (5)!}

Simplify

\frac{7!}{2! (5)!}

=21

RizerMix

Expert2021-12-29Added 656 answers

I see no reason to write the solution for the third time, it is solved in one way

Do you have a similar question?

Recalculate according to your conditions!

Didn't find what you were looking for?