Question

A mother, father, and their two children are to line up for a photo. In how many ways can these four family members line up so that the mother and father are not next to each other? Be sure to show your work.

Answer 1

12

Explanation:

Considering mother and father as one ,

so, total person now are = 3

and they can sit in 3! *2 ways .

(here, 2 is used because mother and father can exchange their position with each other )

so, total number of ways so that mother and father are not next to each other = 4! - 3!*2 = 24 - 12 = 12 ways .