Arithmetic Ability
Permutations and Combinations

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Q.

There are 5 novels and 4 biographies. In how many ways can 4 novels and 2 biographies can be arranged on a shelf ?

View Answer

Correct choice: B

Explanation:

4 novels can be selected out of 5 in 5C4 ways. 2 biographies can be selected out of 4 in 4C2 ways. Number of ways of arranging novels and biographies = 5C4*4C2 = 30 After selecting any 6 books (4 novels and 2 biographies) in one of the 30 ways, they can be arranged on the shelf in 6! = 720 ways. By the Counting Principle, the total number of arrangements = 30 x 720 = 21600
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