SOLUTION: 2)In how many ways can 3 different Mathematics, 2 different Physics and 4 different Chemistry books be arranged on a shelf if A) the Mathematics books are next to each other, B)

Algebra ->  Permutations -> SOLUTION: 2)In how many ways can 3 different Mathematics, 2 different Physics and 4 different Chemistry books be arranged on a shelf if A) the Mathematics books are next to each other, B)      Log On


   



Question 366813: 2)In how many ways can 3 different Mathematics, 2 different Physics and 4 different Chemistry books be arranged on a shelf if
A) the Mathematics books are next to each other,
B)the books are kept in subject groupings?



Answer by sudhanshu_kmr(1152) About Me  (Show Source):
You can put this solution on YOUR website!

A) assume 3 different math books as a single book.
now, total 1 + 2 + 4 = 7 books
no. of ways to arrange 7 books = 7!
group of 3 math books can also be arranged by 3! ways.
so, total no. of ways = 7! * 3!
answer is : 7! * 3!

B) now, assume books of each subject as a single book.
total no. of books = 3
no. of ways to arrange 3 books = 3!
similarly as previous part, physics and chemistry books can be arranged in their group in 2! and 4! ways.

total no. of ways = 3! * 3! * 2!* 4!