Question

1). Evaluate C(20,18).

A) 380
B) 190

2). Evaluate C(6, 6).

A) undefined
B) 1

Answer 1

The answers you are looking for are:

#1 = B) 190

#2=B) 1

Answer 2

Answer:

Ques 1)

                  Option: B  ( B)  190  )

Ques 2)

                              Option: B (  B)  1)

Step-by-step explanation:

We know that the formula of combination C(n,r) is given by:

$C(n,r)=\dfrac{n!}{r!\times (n-r)!}$

Ques 1)

We are asked to evaluate:   C(20,18)

Hence we solve it as follows:

$C(20,18)=\dfrac{20!}{18!\times (20-18)!}\\\\\\C(20,18)=\dfrac{20!}{18!\times 2!}\\\\\\C(20,18)=190$

                  Hence, the answer is: 190.

Ques 2)

Now we are asked to evaluate C(6,6)

Hence, we follows the steps as:

$C(6,6)=\dfrac{6!}{6!\times (6-6)!}\\\\\\C(6,6)=\dfrac{6!}{6!\times 0!}\\\\\\C(6,6)=\dfrac{6!}{6!}\\\\\\Since,\ 0!=1\\\\\\Hence,\\\\C(6,6)=1$

     Hence, the answer is:  1