In a 21 meter race between a turtle and a hare, the turtle leaves 8 minutes before the hare. The hare, by running at an average speed of 0.5 meters per hour faster than the turtle, crosses the finish line 4 minutes before the turtle. What are the average speeds of the turtle and the hare?

2 answers

since time = distance/speed, if the turtle's speed is x m/min, then since .5 m/hr = 1/120 m/min

21/x = 8 + 21/(x+1/120) + 4

The turtle moves at 7/60 m/min = 7 m/hr
The hare moves at 1/8 m/min = 7.5 m/hr

you can check the times to verify that they work out.
how did they get the answer of 7m/pr and 7.5m/hr