Answer: -3
Work shown:
slope = rise/run
slope = (vertical change)/(horizontal change)
slope = (-18)/(6)
slope = -3/1
slope = -3
Therefore, a drop of 18 feet for each 6 feet forward is equivalent to a drop of 3 feet for each 1 foot forward. The further the slope value is from 0, the steeper the slope will be. The closer you get to 0, the more shallow the slope gets. A slope of 0 is a flat horizontal line.