Question

There are  students in a small class. To make a team, the names of  of them will be drawn from a hat. How many different teams of  students are possible?

Answer 1

`e.g\\a\ small\ class\ has\ 15\ students\ and\ we\ will\ choose\ 3-person\ team\\\\the\ number\ of\ possible\ teams\ is\\\\ {n \choose k}={15 \choose 3}= (15!)/(3!\cdot(15-3)!)= (12!\cdot13\cdot14\cdot15)/(2\cdot3\cdot12!) = (13\cdot2\cdot7\cdot3\cdot5)/(2\cdot3) = 13\cdot7\cdot5=455`