Question

A group consists of 10 kids and 2 adults. On a hike, they must form a line with an adult at the front and an adult at the back. How many ways are there to form the line?a. 4.9!b. 2.99!c. 11!d. 11!/2

Answer 1

Answer:

b. 2.9!

Explanation:

There are is a mistake in the question.

Suppose the group consist of 10 kids and 2 adults, the number of ways in which they can form the line is:

= 2! 10!

= 2× 1× 10!

= 2.10!

But since that is not in the given option.

Let assume that the group consists of 9 kids and 2 adults, the number of ways in which they can form the line is:

No of ways the kids can be permutated =  9 ways

No of ways the adult can be permutated  = two ways.

Thus; the number of ways in which they can form the line = 2! 9!

= 2 × 1× 9!

= 2.9!