I'm not sure why people are downvoting me. Not only did I show Op how to solve the original problem their friends had, but I gave them an Ethics lesson.

Some people look at pearls and turn into swine, just because I didn't tickle their bellies. It's a shame. This idea that unless someone can save face, they have to reject the lesson whole cloth... It's costly to our culture. When someone is right, just update and correct your beliefs, and feel no shame.