# Permutations & Combinations :Revision

- Author:
- Sangeeta Gulati

- Topic:
- Combinatorics

## Q1

Find the number of ways in which 5 boys and 5 girls be seated in a row so that no two girls may sit together.

## Q2

How many words each of 3 vowels and 2 consonants can be formed from the letters of the word INVOLUTE?

## Q3

In an examination a candidate has to pass in each of the four subjects. In how many ways can he fail?

## Q4

If , find n.