Question

How many ways can 6 people be chosen and arranged in straight line if there are 8 people to choose from? a. 48.b. 720.c. 20, 160.d. 40, 320.

Answer 1

Answer:

C. 20,160

Step-by-step explanation:

This question bothers on permutation since we are to select a some people out of a group of people and then arrange in a straight line. If r object are to be arranged in a straight line when selecting them from n pool of objects. This can be done in nPr number of ways.

nPr = n!/(n-r)!

Selection of 6 people out of 8 people can therefore be done in 8C6 number of ways.

8P6 = 8!/(8-6)!

8P6 = 8!/2!

8P6 = 8*7*6*5*4*3*2!/2!

8P6 = 8*7*6*5*4*3

8P6 = 56*360

8P6 = 20,160

Hence this can be done in 20,160 number of ways