Q. If is continuous function at then equals to

 2399  303 JamiaJamia 2012 Report Error

Solution:

There are 7 letters in the word FAILURE. To include F in every 4 letters word, we first select four letters from the 7 letters of the word FAILURE such that F is included in every selection. This can be done by selecting three letters from the remaining six letters. ie, in ways. Now there are 4 letters in each of selections. Also every selection contains letters which can be arranged in 4! ways. Hence, the required number of four letter words