Permutation And Combination Ques 12
Question-
On a shelf there are 4 books on Economics, 3 books on Management and 4 books on Statistics. In how many different ways can the books be arranged so that the books on Economics are kept together?
(1) 967680
(2) 120960
(3) 5040
(4) 40320
(5) None of these
(Punjab & Sind Bank PO Exam. 23.01.2011)
Show Answer
Correct Answer: (1)
Solution: (1)
Books on Economics are to be kept together. Hence, we are to arrange 3 books on management, 4 books on Statistics and one book on Economics.
These can be arranged in 8! ways. Again, 4 books on Economics can be arranged together in 4 ! ways.
$\therefore$ Total number of arrangements $=8 ! \times 4 !=967680$
$[n !=1 \times 2\times 3 \times 4 \ldots(n-1)(n)]$
BETA
