In how many different ways can 4 persons be seated in consecutive seats in a row of 7 seats?

Text Solution

Answer : 360

Solution : 1st person can be seated in 6 ways , 2nd person in 5 ways, 3rd person in 4 ways and 4th person in 3 ways. <br> Required number of ways `=(6xx5xx4xx3)=360.`

Recommended textbooks for you

A First Course in Probability (10th Edition)

ISBN:9780134753119

Author:Sheldon Ross

Publisher:PEARSON

A First Course in Probability

ISBN:9780321794772

Author:Sheldon Ross

Publisher:PEARSON

in how many different ways can 4 persons be seated in a consecutive row of seven seats??
7 position 4 = P(7,4) = 7�6�5�4 = 840 ---------------------------------------------------- 2. a shelf contain 5 red books, 4 blue books, and 3 green books. how many different orders can they be arranged if all books of the same color must kept together?First, there are P(3,3) = 3! ways we can choose the order of colors, that is, (Red,Blue,Green), (Red,Green,Blue), (Blue, Red,Green), (Blue,Green,Red), (Green,Red,Blue), (Green,Blue,Red) Then for each of those 3! ways, there are P(5,5) = 5! ways to arrange the 5 red books, P(4,4) = 4! ways to arrange the blue books, and P(3,3) = 3! ways to arrange the green books. Answer 3!�5!�4!�3! = 6�120�24�6 = 103,680 ways. Edwin