Crossing the desert

Posted: September 22, 2009 in M@th puzzles
Tags: , ,

You have to cross a large desert that is 1,000 km long. You have a horse and 3,000 apples. The horse can carry a maximum of 1,000 apples at any time. For every kilometer that the horse needs to travel, it eats one apple before it can start moving. What is the maximum number of
uneaten apples that the horse can transport to the other end of the desert?

Try 2 solve this.Mail me for more info..

  1. Aadya says:

    I hope it has nothin to do with, man walks down 1000 kms all by himself without using a horse!!!

  2. Namdor says:

    Answer is 534. How? Let’s call the departing point Km 0. You start off by giving one apple to the horse (-1) and carrying 1000 apples to Km 1, leave them there, let the horse grab another one (-1) and go back with nothing where the rest of the apples are (Km 0). Let him have another apple (-1) and take 1000 with you, which leaves 2000 at Km1 and 1000 at Km0. Once again, give another apple to the horse (-1) and go back to Km 0 with nothing. Give the horse an apple (-1) and take the last 1000 to Km 1. Now repeat 999 times. However, there’s a catch: As you do this, you will progressively lose more and more apples to the point that your stock changes from 3000 to 2000 to 1000. Therefore, you need to take into consideration this when counting the “round trips” your horse is gonna make to gather all apples kilometer after kilometer.
    This leaves you with 3000 – (5 x 200) – 3 (333) – 467 = 534

    • Namdor,
      Good job.. U got the right solution.. πŸ™‚ Hope u enjoyed solving this puzzle.. Try to solve more puzzles and share if u have good ones thru mail.. πŸ™‚

    • revathy says:

      I cant understand this solution so deeply……could u explain me clearly with how this equation came??please…………iam helpless

      • Revathy,

        I will try to explain the solution in a more simpler way.
        Divide the whole 1000Km to 3 parts. Lets say Point O is the start point , Point A at 200th km. Point B 333 Km far from Point A (533th KM) then Point C is the Destination(467 Km from C).

        Journey to Point A
        Carry 1000 Apples from O to A(200 km from O). Camel eats 200 Apples. Drop 600 in A and carry 200 to travel back to O. Take another 1000 similarly. So at A we have (600+600+800=2000) and camel Ofc.

        Journey to Point B
        Carry 1000 Apples from A to B(333 Km from A). Camel eats 333 apples and drops 334 apples and carries 333 back to A. Similar way (334+667 = 1001)

        Journey to destination
        Camel eats one apple to start. And Carries 1000 in its back. To travel next 467 Kms it needs 466 Apples more. So (1000-466 = 534) finally we have 534 apples in destination.

        Hope u understood.

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