A pair of kids and a pair of adults decided to compete in a three-legged race. The kids got to start 10 yards ahead of the adults, since they had shorter legs. When they were told to start, the kids hobbled forward at a rate of 2 yards per second, and the adults hobbled after them at a rate of 3 yards per second. Soon they were side-by-side. How long did that take?
10 seconds
Kids 10 sec go 20 yds + initial 10 yards
Adults 10 sec go 30 yds