Your equation is just to multiply 480 by 3/4.
Easy way to do these quick.
480 (3/4) is the same as (480 * 3) / 4
480 / 4 = 120
By simplifying, you are left with just 120 * 3 in the numerator
120 * 3 = 360
There are 360 people on the plane.
If you need to check your answer:
360 / 480
Take away the zeros at the end by dividing both by 10
36 / 48
Divide both by 6
6 / 8
Now divide by 2
3 / 4