A lawn measuring 200x50 ft with a 60x25 ft house, a 25 ft diameter pool, and a 10x40 ft driveway is treated at 3 oz per 1000 sq ft. How many ounces are needed?

• A. 22 oz
• B. 24 oz
• C. 26 oz
• D. 28 oz

Answer: (B)

The main idea is to apply the treatment only to the lawn area, then convert that area into ounces using the rate given.

First, find the lawn area by removing non-lawn spaces from the total area. The lawn is 200 by 50 ft, which is 10,000 square feet. The house is 60 by 25 ft, or 1,500 sq ft. The pool is a circle with diameter 25 ft, so the radius is 12.5 ft and the area is π(12.5)^2 ≈ 490.9 sq ft. The driveway is 10 by 40 ft, or 400 sq ft. Subtracting these from the total gives the lawn area ≈ 10,000 − 1,500 − 490.9 − 400 ≈ 7,609.1 sq ft.

At a rate of 3 oz per 1,000 sq ft, the amount needed is (7,609.1 / 1,000) × 3 ≈ 22.83 oz.

You can’t use a fraction of an ounce, so you round up to the next whole ounce, which would be 23 oz. Since 23 oz isn’t listed among the choices, the closest available option is 24 oz, which is the best choice among the given answers.