Question

A school director must randomly select 6 teachers to participate in a training session. There are 30 teachers at the school. In how many different ways can these teachers be selected, if the order of selection does not matter?

Answer 1

Order of selection doesn't matter, so use combinations (rather than permutations), so: \[ {30 \choose 6}=\frac{30!}{6!(30-6)!}\]