Using the normal soil setting formula, what is the recommended depth for a soil depth of 50 feet?

• A. 6 ft
• B. 7 ft
• C. 5 ft
• D. 8 ft

Answer: (B)

The test uses a fixed proportion to turn soil depth into the recommended setting depth. The normal soil setting formula typically uses a 1/7 rule, so you divide the soil depth by 7. For a depth of 50 feet, 50 ÷ 7 equals about 7.14 feet, which rounds to 7 feet. That is why the best answer is 7 feet. The other options don’t align with the 1/7 rule: 6 feet would be too shallow, 8 feet a bit deep, and 5 feet even more shallow relative to 50 feet.