I don't have an exact answer for you, but I can give a little more information. I see someone posted all the tech specs of the 747 and had some numbers up, but there are a lot of factors that play into fuel burn rate. First off, since 747's were first built, they have had 3 different engine options available to the customers. Rolls Royce, Pratt and Whitny, and GE. refer to http://en.wikipedia.org/wiki/Boeing_747#Powerplants for specifics. Obviously different engine manufacturer's are gonna have different performance ratings, I.E. Max thrust and fuel burn. Also take into consideration take off location, weather conditions, and aircraft load. obviously an empty 747 taking off out of some locatin at sea level on a 59 degree farenheit day is going to require much less to get off the ground compared to a fully loaded 747 taking off out of say denver on a hot day. Keep in mind that Density altitude and Pressure altitude have a huge effect on fuel consumption rates. Basically the correct answer to your question is that there isn't enough information to determine the answer. Primary missing components to the question are, Weather conditions at time and location of take off and aircraft load. Then the best way to determine fuel burn is to perform a fuel consumption check. Note fuel quantity at start time, start timer once take off profile is initiated (probably on engine run up once taking active runway), note fuel quantity at stop time which would be once the aircraft is established in a cruise profile. I assume that climb out would be part of the take off profile. subtract stop time fuel quantity from start time fuel quantity to come up with ammount of fuel burned. Meaured in pounds on an aircraft of that size. then you figure out how long your fuel check lasted. with thoes two number you could use an E6B flight computer to determine your acctual burn rate for that profile. Hope that helps a little. I am a commercial rotorcraft pilot and also an A and P aircraft mechanic. I deal with this kind of stuff everytime I fly. :) If some of my answer didn't make sense or you have questions, feel free to contact me.