Question

There are four children in Mr. Martin’s class. Three of them will be selected to be hall monitors. How many combinations of hall monitors are possible?

Answer 1

Answer: 4

Explanation

We get all possible triples of children from four children by choosing one child from four ones, which is not included into a triple, so four combinations of hall monitors are possible.

We get the same answer, using the combinatorial analysis formula of the number of possible combinations of 4 objects taken 3 at a time: C(4,3)=4!/3!/(4-3)!=4.