Question

Nola hiked down a trail at a steady rate for 10 minutes. Her change in elevation was -200 feet. Then she continued to hike down for another 20 minutes at a different rate. Her change in elevation for this part of the hike was -300 feet. During which portion of the hike did she walk down at a faster rate ? Explain your reasoning

Answer 1

Her speed is minutes per foot or feet per minutes, so we have 10 minutes/-200 feet=-1/20 feet. Since it doesn't matter that it's negative (we care about the speed, and you can't have negative speed), we get the absolute value (1/20). For the next 20 minutes, we have |20 minutes/-300 feet|=1 minute/15 feet. Since 1/20=0.05 and 1/15 is 0.0666667, 1/15 is clearly higher and the 20 minute portion was at a faster rate