Answer:
1 gallon.
Step-by-step explanation:
The quantity of brown paint is 8 gallons.
To get the shade of brown paint he desired, gallon of white paint required to be mixed with 2 gallons of brown paint.
Here, Hamza wants to lighten the 8 gallons of brown paint, so, by using the elementary method,
For 2 gallons of brown paint, he required gallon of white paint.
So, for 1 gallon of brown paint, he required gallon of white paint.
Now, for 8 gallons of brown paint, he required gallon of white paint.
Hence, Hamza needs to buy 1 gallon of white paint to light the 8 gallons of brown paint.