1. The problem statement, all variables and given/known data You and a friend each drive 50 km. You travel at a uniform speed of 91.4 km/hr and your friend travels at a constant speed of 88.3 km/hr. How long will you wait for your friend? 2. Relevant equations 3. The attempt at a solution So I thought I could just set up a ratio and cross-multiply to get the hrs. traveled by each person. I got .547hrs. for "me" and .566hrs. for "my friend". Then subtract, the difference being the answer. However, I am doing this on a computer-generated exercise and it is telling me that .019hrs. is incorrect. Why isn't this right?