Okay, so to solve this question, we need to get from 18 (hours) to 9. To do this, we obviously divide 18 by 2. Since we did this, we now have to do the same thing with the other side ($252.) 252 divided by 2 is 126. This means that if Chau made $252 in 18 hours, he will make $126 in 9 hours.
