Question

In how many ways can $21$ English and $19$ Hindi books be placed in a row so that no two Hindi books are together :

• A. 1540
• B. 1450
• C. 1504
• D. 1405

Answer 1

Answer: (A)

First we placed the 21 English books in alternate position.
So, there are 22 vacant place left.
$\therefore$ The total number of ways $={}^{22}{C}_{19}$
$=\frac{22\times 21\times 20}{3\times 2\times 1}$
$=1540$