Out of 7 consonants and 4 vowels, how many words of 3 consonants and 2 vowels can be formed ?
In how many ways can 21 books on English and 19 books on Hindi be placed in a row on a shelf so that two books on Hindi may not be together ?
How many 3-digit numbers can be formed from the digits 2, 3, 5,6, 7 and 9, which are divisible by 5 and none of the digits is repeated ?
A box contains 2 white balls, 3 black balls and 4 red balls. In how many ways^can 3 balls be drawn from the box, if at least one black ball is to be included in the draw ?
From a group of 7 men and ,6 women, five persons are to be selected to form a committee so that at least 3 men are there on the committee. In how many ways car. it be done ?