For a rectangular tank measuring 10 ft high, where 20 ft wide and 40 ft long, how many coats of paint are required?

• A. One coat
• B. Two coats
• C. Three coats
• D. Four coats

Answer: (B)

To determine the number of coats of paint required for a rectangular tank, it is important to first calculate the total surface area that needs to be painted. The surface area includes both the sides and the top of the tank, as the bottom is typically not painted.

The dimensions of the tank are as follows:

• Height: 10 ft

• Width: 20 ft

• Length: 40 ft

The surface area of the four sides of the tank can be calculated using the formulas for the area of rectangles. The area of the two longer sides (each 40 ft long and 10 ft high) is:

Area of longer sides = 2 * (length * height) = 2 * (40 ft * 10 ft) = 800 ft².

The area of the two shorter sides (each 20 ft wide and 10 ft high) is:

Area of shorter sides = 2 * (width * height) = 2 * (20 ft * 10 ft) = 400 ft².

The area of the top (which is 20 ft wide and 40 ft long) is:

Area of the top = width * length = 20 ft * 40 ft = 800 ft².