Yes,you are correct.
The first van carries 8 people.
The second van carries 8 people.
The 3rd van carries the remaining 4 people.
8+8+4=20
3x(4x4 – 5x)
= 12x^5-15x^2

a parallel line to that one above, will have the same exact slope, since parallel lines have the same slope.
He needs 2 cups of sugar if he's tripling the recipe.