15 cars are going to be lined up at a dealership.The first 7 must be convertibles, then next 5must be SUV's, and the last 3 must be vans. Ifthere are 20 convertibles, 10 SUV's, and 8 vansto choose from, how many distinct line ups canbe created?

Respuesta :

Solution

- This is a combination question because we are to choose from a list of items in a distinct lineup.

- The formula for combination is:

[tex]\begin{gathered} ^nC_r=\frac{n!}{(n-r)!r!} \\ \\ where, \\ n\text{ is the total amount of items} \end{gathered}[/tex]

- Also, since the choice or distinct arrangement of the cars independent, we can simply multiply the possible combinations.

- That is,

[tex]\begin{gathered} \text{ Convertible:} \\ ^{20}C_7=77520 \\ \\ \text{ SUV:} \\ ^{10}C_5=252 \\ \\ \text{ Vans:} \\ ^8C_3=56 \end{gathered}[/tex]

- Thus, the possible number of distinct line ups is:

[tex]77520\times252\times56=1,093,962,240\text{ line ups}[/tex]