Thursday, 12 July 2012

Number Elimination Game

There is a box containing 'n' numbers from 1 to 'n'. A person randomly picks 2 of them, say x and y and replaces them with a single number x+y+xy. He continue this until the last number is left. Find the last number remaining?


  1. if we take any set of consecutive no.s from m to n and perform the most general operation on two no.s x,y by replacing them with (x+k)(y+k)-k , then we will get the final no. = (n+k)! - (m+k-1)! ... (in this case k=1, m=1)