42. Emma and Kristin each ran 10 laps (4,000 meters) around a 400-meter track without stopping. Emma ran at a constant speed of 250 meters per minute. Kristin ran at a constant speed of 200 meters per minute. Both Emma and Kristin began running at the same instant. How many laps did Kristin have left to run when Emma had completed her run?

Answer and Explanation

Your Answer is

Correct Answer is J

Explanation

First of all, when Emma finished, she took 4000÷250=16 minutes. At this time, Kristin ran 16 × 200=3200 meters, so Kristin had 4000-3200=800 meters left, which is 800÷400=2 circle