If it took 2/5 gallon of paint to cover 282 square feet of wall in tom’s garage, how much more paint will he need to paint an additional 423 square feet of wall?

3/5 gallons of more paint

Explanation:

Given:

Paint required for 282 square feet of area = 2/5 gallon = 0.4 gallons

thus,

by applying the concept of unitary method we have

paint required for 1 square feet of area = (0.4 gallons)/282

therefore,

the paint required for 423 square feet of area = gallons

or

the paint required for 423 square feet of area = 0.6 gallons = gallons

hence, 3/5 gallons of more paint will be required.