Let the speed of walking of James = x mile/hour
speed of jogging = 2x mile/hour
9/2x + 1.5/x = 2
or, (9 + 3)/2x = 2
or, 12 = 4x
or, x = 3
Average speed of walking = 3 mile/hour
Average speed of jogging = 2 * 3 = 6 mile/hour
Just multiply all of the numbers and you will get 1472 ft3
