Melanie went to the hardware store and bought gallons of white paint and gallons of black paint. how many gallons of paint did melanie buy altogether?

a student solved the problem this way:

melanie bought gallons of paint.

use a similar strategy to solve this problem.

juan bought gallons of black paint, gallons of white paint, and a inch paint brush.

how many gallons of paint did juan buy altogether?

a.
gallons

b.
gallons

c.
gallons

d.
gallons