Question

Evaluate the given expressions 5P2

Answer 1

`^5P_2=20`

d is the correct option.

Explanation:

We have to find the value of the expression
`^5P_2`

The formula for permutation is given by

`^nP_r=(n!)/((n-r)!)`

Here, n = 5, r = 2. Thus plugging these values in the formula, we get

`^5P_2=(5!)/((5-2)!)`

On simplifying, we get

`^5P_2=(5!)/(3!)\\\\=(3!*4*5)/(3!)\\\\=4*5\\\\=20`

Therefore, the value of the expression is 20.

d is the correct option.

Answer 2

d. 20

Explanation:

The number of permutations of n things taken k at a time is ...

nPk = n!/(n-k)!

5P2 = 5!/3! = 5·4 = 20