Question

A can of white paint costs $16 while a can of green paint costs $20. Susan is mixing 12 cans of paint and will pay $19 per can for the mixture. How many cans of white paint will she purchase?

Answer 1

Let g= green paint
Let w= white paint

So

g+w=12

20g +16w= (12)(19)

Rearrange the first equation

g=12-w

Substitute into the second equation.

20(12-w) +16w= 228

Solve for w

240 -20w +16w=228

12=4w

3=w

So she bought 3 cans of white paint and 9 cans of green.