On a shelf, 2 books of Geology, 2 books of Sociology and 5 of Economics are to be arranged in such a way that the books of any subject are to be together. Find in how many ways can this be done?
Choices.
A) 2880  B) 2778  C) 2682  D) 8222  E) 6282
Explanation:   There are books of 3 subjects (Geology, Sociology and Economics), hence they can be arranged in 3! (3 * 2 * 1) = 6 ways.   Further, in each category (subject), books are to be arranged in different order, we get,   Required number of ways: 3! * [2! * 2! * 5!] = 2880   2880NSWER: 2880
<result>A</result>
On a shelf, 2 books of Geology, 2 books of Sociology and 5 of Economics are to be arranged in such a way that the books of any subject are to be together. Find in how many ways can this be done?