Final answer:
The scale of the drawing is 1/2 inch to 1 foot.
Step-by-step explanation:
The plumber can determine the scale of the drawing by comparing the height on the drawing to the actual height of the wall. The height of the wall on the drawing is 2 inches, and the actual height of the wall is 4 feet. Since 1 foot is equal to 12 inches, the scale can be calculated as follows:
2 inches / 12 inches = 4 feet / x
Now, cross-multiply and solve for x:
2x = 48
x = 48 / 2
x = 24
Therefore, the scale of the drawing is 1 inch to 24 feet, which can be simplified as 1/2 inch to 1 foot.