MATH 1040 - Introduction to Statistics

Practice Question 11.2.3

Calculate the value of \(\frac{7!}{4!}\).

Answer to Practice Question 11.2.3

There are two ways to answer this. The first is doing the factorials first, then the division:

\[\frac{7!}{4!} = \frac{5040}{24} = 210\]

The other is way is valuable as well, especially as we talk about permutations and combinations in the next to pages. Here, we note that some terms will cancel out:

\[\frac{7!}{4!} = \frac{7\times 6\times 5\times 4\times 3\times 2\times 1}{~~~~~~~~~~~4\times 3\times 2\times 1} = 7\times 6\times 5 = 210\]