I was recently browsing through an archive of Calvin and Hobbes comics when I came across the storyline about Calvin taking a math quiz and pondering the answer to the following problem.
“Jack and Joe leave their homes at the same time and drive towards each other. Jack drives at 60 mph, while Joe drives at 30 mph. They pass each other in 10 minutes. How far apart were Jack and Joe when they started?”
To solve the problem, Calvin imagines himself as Tracer Bullet and begins an investigation filled with danger and peril that eventually leads him to a suspect known as Mr. Billion. However, as the test papers are being collected, Calvin’s classmate Susie tells him she thinks the answer is 15.
Since reading that strip I began to wonder how to solve such a problem. I decided to start by calculating how far Jack drives in 10 minutes at 60 mph. Then I recalled the formula for calculating distance when the variables for time and speed are known. The more I tried solving the problem the more confusing it got. It’s been too long since I used algebra and my math skills have never been very sharp. So I turned to the Internet and found this web site that has the simple solution to the problem.
Turns out Susie was right.