It will take 8 minutes. You use a proportion 5/1=2400/x you use 2400 because 2.4km=2400 meters and u need to use the same unit of measurement. so cross multiplying gives you 5x=2400 which is equal to 480. BUT this is 48 seconds, and it asks you how many minutes, not seconds. So, you divide by 60 because there are 6 seconds in a minute, and you get 8.
By calculus or elementary geometry, we know that the formula for the volume of a cone, given pi (the constant), its height h and its radius r is: Lets solve this relation for the radius: Now we have found a general formula that gives us the radius of a cone, given its volume and height. We need only substitute height (20in) and pi=3.14 to get the numerical equation: r=0.2185*