A country wants to use 5 coin denominations to pay for all purchases from 1 to 29 in this currency. however only two coins are allowed in each transaction, whether one is given, two are given, or one is given and one is received doesn't matter. Show that at least six coins will be needed.

Question

anonymous · Answer

umm isn't this from the maths challenge which youre supposed to do yourself?

anonymous · Answer

very acute, i have tried, and as far as i can find, it is possible in theory to do, just not in practice, i haven't yet found a way to prove or disprove it either way.