**Factorial**

There is a notation which will be used many times in the next explanation. That notation is called factorial. Factorial is notated by: “!”. Factorial is the short writing of a series of multiplication of positive number in a decreasing order until 1.

Factorial can be defined as the following:

And so on.

Generally the factorial of a numeral is formulated as the following:

*n!=n∙(n-1)∙(n-2)∙…∙1=n∙(n-1)!*

**Example 5:**

**Exercise Competency Test 5 (QnA factorial concept)**

1. 6!=⋯

A. 720 B. 620 C. 520 D. 360 E. 6

Answer: A, explanation:

A. 15! B. 10! C. 8! D. 7! E. 6!

Answer: E, explanation:

A. 336 B. 326 C. 316 D. 236 E. 226

Answer: A, explanation:

A. 70 B. 50 C. 35 D. 25 E. 10

Answer: C, explanation:

*n*!/(

*n*-1)!=⋯

A.

*n*C.

*n*-2 E. 1/

*n*

B.

*n*-1 D.

*n*

^{2}–

*n*

Answer: A, explanation:

*p*and

*q*are the roots of quadratic equation

*x*

^{2}-14

*x*+48=0. If

*p>q*, then the value of

Answer: C, explanation:

The

*n*=⋯

A. 6 B. 5 C. 4 D. 3 E. 2

Answer: B, explanation:

Then the value of n which satisfy the equation is equal to ….

A. 4 B. 5 C. 6 D. 7 E. 8

Answer: B, explanation:

Embed the link of this post