The number of permutations of n different things taking r at a time when 3 particular things are to be included is:
View full solution →- $^{\text{n}-3}\text{P}_{\text{r}-3}$
- $$$^{\text{n}-3}\text{P}_{\text{r}}$
- $^{\text{n}}\text{P}_{\text{r}-3}$
- $\text{r! }^{ \text{n}-3}\text{C}_{\text{r}-3}$