Making Dollar riddle

924.5K Views
Answered

You are given “n” coins of denominations 1, 0.5, 0.25, 0.1, 0.05 and 0.01 (6n coins altogether). You are then asked to choose n out of these 6n coins that sum up to exactly 1. What is the smallest n for which this is impossible?

Share
Add Comment

  • 2 Answer(s)
    Best answer

    n=1; just select the coin with denominations 1

    CugelTheWise Expert Answered on 20th September 2018.
    Add Comment

    3

    bornkira Starter Answered on 10th January 2019.

    Your answer is not correct.
    You can make 1 with a coin of 0.5 and 2 of 0.25, using 3 coins.

    My first answer was wrong as well because I read the possible instead of impossible.
    I come up to 76 coins (6 x 0.05 and 70 x 0.01).
    I think the answer is 77. With 75 coins of 0.01 you can use only 2 coins to make 0.25

     

    on 10th January 2019.

    You are right. I realised it just after commenting it but didn’t knew how to delete it ?

    on 11th January 2019.
    Add Comment
  • Your Answer

    By posting your answer, you agree to the privacy policy and terms of service.
  • More puzzles to try-