Use app×
Join Bloom Tuition
One on One Online Tuition
JEE MAIN 2025 Foundation Course
NEET 2025 Foundation Course
CLASS 12 FOUNDATION COURSE
CLASS 10 FOUNDATION COURSE
CLASS 9 FOUNDATION COURSE
CLASS 8 FOUNDATION COURSE
0 votes
180 views
in Permutations by (24.8k points)
closed by

Four books, one each in Chemistry, Physics, Biology and Mathematics, are to be arranged in a shelf. In how many ways can this be done?

1 Answer

+1 vote
by (27.0k points)
selected by
 
Best answer

Given : The total number of books = 4 

To find : Number of ways in which these 4 books can be arranged in a shelf 

Formula used : 

Number of arrangements of n things taken all at a time = P(n, n) 

∵ P(n, r) = \(\frac{n!}{(n-r)!}\)

∴ The total number of ways 

= the number of arrangements of 4 things taken all at a time 

= P(4, 4)

\(\frac{4!}{(4-4)!}\)

\(\frac{4!}{0!}\) 

{∵ 0! = 1} 

= 4 × 3 × 2 × 1 

= 24

Hence,

Number of ways in which these 4 books can be arranged in a shelf are 24.

Welcome to Sarthaks eConnect: A unique platform where students can interact with teachers/experts/students to get solutions to their queries. Students (upto class 10+2) preparing for All Government Exams, CBSE Board Exam, ICSE Board Exam, State Board Exam, JEE (Mains+Advance) and NEET can ask questions from any subject and get quick answers by subject teachers/ experts/mentors/students.

...