Multiple choice general knowledge science & technology The gradient of a stream that drops 10 feet over a horizontal distance of two miles is: 20 feet per mile 10 feet per mile 5 feet per mile 2.5 feet per mile Reveal answer Fill a bubble to check yourself C Correct answer Explanation Gradient is calculated as vertical drop divided by horizontal distance: 10 feet divided by 2 miles equals 5 feet per mile. This represents the stream's average slope over that reach.