1. After rolling the frsrt ball of a frame in a game of 10 -pin bowling, how many many different pin confingurations can remain
2. Assuming that what is wanted is to seat 7 people in a row with 7 chairs. In how many ways can we seat these 7 people in the chairs
3. How many ways can a boy and a girl be selected to decorate for a birthday party from a club consisting of nine members when three are boys and the other six are girls?
4. How many two -digit numbers can be formed by using the digits 1,3,5,6,7 and 8 without repetition?(i.e. 33 nor 11 are allowed.)