Hello, Tom!

Suppose that I have 10 computer games that i need to play.

Only one game may be played at any time.

In how many ways can the games be run if:

a) Four of the games are considered better the others and played first

The first four can be ordered in ways.

The last six can be ordered in ways.

Hence, there are: . ways.

There are: . ways.b) There is no restriction on the playing order of the games

c) The games can be separated into order into:

three in top priority (played first),

five in medium (played straight after the top three),

five in low (played last). . . . . 13 games?

The top priority games can be ordered in ways,

the medium priority games can be ordered in ways,

the low priority games can be ordered in ways.

Hence, there are: . ways.