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

Ques 1)

Option: B ( B) 190 )

Ques 2)

Option: B ( B) 1)

Explanation:

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

`C(n,r)=(n!)/(r!* (n-r)!)`

Ques 1)

We are asked to evaluate: C(20,18)

Hence we solve it as follows:

`C(20,18)=(20!)/(18!* (20-18)!)\\\\\\C(20,18)=(20!)/(18!* 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)=(6!)/(6!* (6-6)!)\\\\\\C(6,6)=(6!)/(6!* 0!)\\\\\\C(6,6)=(6!)/(6!)\\\\\\Since,\ 0!=1\\\\\\Hence,\\\\C(6,6)=1`

Hence, the answer is: 1