Answer
Number of ways that the first three finishers come in = $6_{{P}{_{3}}}$ = 120
Work Step by Step
Total number of automobile = 6
Number of best finishers = 3
Number of ways that the first three finishers come in = $6_{{P}{_{3}}}$ = $\frac{6!}{(6 - 3)! }$ = $\frac{6!}{3! }$
= $\frac{6\times5\times4\times3!}{3! }$
= $6\times5\times4$
= 120