Answer:
D. [tex]32,400=216\cdot a[/tex]
Step-by-step explanation:
Let [tex]a[/tex] equals the number of airplanes.
Last week, the airline use only airplanes that have a capacity of 216 passengers, then [tex]a[/tex] airplanes can hold
[tex]216\cdot a[/tex] passengers.
If 32,400 passengers are in total, then
[tex]32,400=216\cdot a[/tex]