In September 1999, the Mars Climate Orbiter crashed onto the surface of Mars due to a calculation error. (It even happens to NASA scientists!) There was a miscommunication between one team of engineers that was working in English units of pounds per second of thrust, and the rest of the NASA team that was working in metric units of newtons per second of thrust. When the lander approached Mars to go into orbit, it thought the English units were metric units, misjudged how fast it was going, entered the atmosphere too soon, and crashed. Write a real-world problem that gives two different rates that must be converted to unit rates and then compared.