Try it on paper first. A hint, the key idea and the worked solution are here when you need them.
A team of is picked from players, who include Kiran and Joseph. In how many ways can the team be picked if (a) both of them play, (b) neither plays, (c) exactly one of them plays?
If someone must be in, choose the rest from the others; if someone must be out, choose from the others. Choices from separate groups multiply. For "at least one", subtract the selections with none from the total. To make words or codes, select first, then arrange the chosen things in ways.
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. Both play. Choose more from the other : .
Step 2. Neither plays. Choose all from the other : .
Step 3. Exactly one. Pick which one in ways, then more from : .
Step 4. Check. , every team.
Answer: (a) , (b) , (c) .
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