Question

Draw and use a double number line diagram to model and solve the problem below.

Leah gets to paint her room since she bought a new bedspread set. Two gallons of paint covers 800 square feet. How many gallons of paint will Leah need to paint her entire room, which is 1,200 square feet?
A.
3.5 gallons
B.
1.5 gallons
C.
4.5 gallons
D.
3 gallons

Answer 1

Set up a double number line with square feet on the top line and gallons on the bottom line.

Top (sq ft): 0 ---- 400 ---- 800 ---- 1200
Bottom (gal): 0 ---- 1 ---- 2 ---- 3

Reasoning:
- 2 gallons cover 800 sq ft, so 1 gallon covers 400 sq ft (800 ÷ 2 = 400).
- 1200 sq ft is three times 400 (1200 ÷ 400 = 3), so Leah needs 3 gallons.

Answer: D. 3 gallons.