Answer: 336 ways
Step-by-step explanation:
Given
Sam has 8 models and he needs to place 3 on a shelf
3 models can be selected out of 8 in [tex]^8C_3[/tex] ways
It can further be arranged among themselves in [tex]3![/tex] ways
Therefore, total number of ways are
[tex]\Rightarrow 3!\times ^8C_3\\\\\Rightarrow 3!\times \dfrac{8!}{3!5!}\\\\\Rightarrow 8\times 7\times 6=336\ \text{ways}[/tex]
