36th Swedish 1996 Problem 2 Find n > 1 so that with stamp denominations n and n+2 it is possible to obtain any value ≥ 2n+2.
n=3 Solution 2n+3 - (n+2) = n+1, and 2n+3 < 2(n+2), so the only possible way to get 2n+3 is as n+n+n. Hence n = 3. To show that n=3 works, note that 8 = 3+5, 9 = 3+3+3, 10=5+5. Then by adding additional 3s we can get any larger number. Thanks to Suat Namli 36th Swedish 1996 © John Scholes jscholes@kalva.demon.co.uk 16 January 2004 Last corrected/updated 16 Jan 04