wu :: forums - Print Page


    
      
        wu :: forums
        (http://www.ocf.berkeley.edu/~wwu/cgi-bin/yabb/YaBB.cgi)
      

        riddles >> medium >> Flying Around the Globe
        
(Message started by: Barukh on Aug 19^th, 2008, 4:05am)

Title: Flying Around the Globe
Post by Barukh on Aug 19^th, 2008, 4:05am

The aircraft division manager got a mission: he needs to set a single airplane on a flight around the globe once in every 15 consecutive weeks.

The following is known about flight conditions:

1. There is only one available airport, so all airplanes should start and return to it.
2. The amount of fuel one airplane can carry is enough for flying 1/2 of the globe.
3. Planes may refuel each other in the air at any given time.
4. At the airport, there are 10 airplanes and an amount of fuel sufficient to fully load 89 airplanes.

Mission impossible?

Title: Re: Flying Around the Globe
Post by towr on Aug 19^th, 2008, 4:19am

How fast do the planes fly; and how long does the total amount of fuel need to last; is that the yearly budgeted fuel?

If not for the above issues, it's virtually the same problem as in this thread (http://www.ocf.berkeley.edu/~wwu/cgi-bin/yabb/YaBB.cgi?board=riddles_easy;action=display;num=1214630019).

Title: Re: Flying Around the Globe
Post by Barukh on Aug 19^th, 2008, 9:10am

on 08/19/08 at 04:19:53, towr wrote:

If not for the above issues, it's virtually the same problem as in this thread (http://www.ocf.berkeley.edu/~wwu/cgi-bin/yabb/YaBB.cgi?board=riddles_easy;action=display;num=1214630019).

Yes, that's the problem I had in mind and overlooked.

rmsgrey's solution is better than one I had in mind. That may be because I tacitly assumed something that was not specified in the conditions. So, let me change the following statement:

3a. Planes may refuel each other only on their way forward. That is, once the plane turns back to the airport, it cannot refuel and cannot be refueled.

I.e. the airplane to fly around the globe can be refueled at any time, but not other planes.

Is mission possible under these new conditions?

Refering to the solution in the original thread: rmsgrey's solution uses 5 tanks per week, but doesn't satisfy the above condition (one of the planes is refueled on its return route). BenVitale's solution satisfies the condition, but uses 6 tanks per week.

Sorry for inconvenience...