<t>A stupid mathematical problem!!!in a nutshell, I loaned a guy $4,000 then another day i loaned him a further $2,000. When I asked him to repay it, he said mathematically he did not owe me anything. I asked for prove, he said like this:let a = 4000, b = 2000, and c = 6,000a + b = cmultiply both si...