A 30 foot long driveway has a 5% slope from one end to the other. What is the rise or change in grade?

To determine the rise or change in grade of a 30-foot-long driveway with a 5% slope, we first need to understand what a percentage slope signifies. A 5% slope indicates that for every 100 units of horizontal distance, there is a rise of 5 units.

To calculate the change in grade over a 30-foot distance, we can use the formula:

Change in grade = (Slope percentage / 100) × Horizontal distance

Substituting the values:

Change in grade = (5 / 100) × 30 feet = 0.05 × 30 feet = 1.5 feet

Since 1 foot is equivalent to 12 inches, we convert the rise from feet to inches:

1.5 feet × 12 inches/foot = 18 inches

Therefore, the change in grade is 18 inches, confirming that this option is indeed correct. Understanding this concept is crucial for effective grading and excavating, as it impacts water drainage and construction design.