Math Class IX Chapter 7- permutation Combination and Probability

True or False
1. Permutation of n different objects is a subset of given objects? 2. Number of signals that can be given by 5 flags of different colours using 3 flags at a time is 120? 3. Five boys and four girls can be seated on a bench so that the boys and the girls can occupy alternate seats in 20? 4. Four persons can be seated on a round table in 6 ways? 5. Number of diagonals that can be formed by joining the vertices of 10 sided figure is 35?