2016-04-17 14:24:06
Starting at home, ishann traveled uphill to the grocery store for 12 minutes at just 15 mph. Then he traveled back home along the same path downhill at a speed of 30 mph. What is his average speed for the entire trip from home to the grocery store and back?
2016-04-17 21:08:41

trip uphill to the store: distance = speed * time                = (15mph)*(12minutes/60 minutes per hour)                = (15mph)*(0.2 hours)                = 3 miles trip downhill back home is along the same path so the trip downhill was also equal to 3 miles. So the the entire trip was a distance of 6 miles 3 miles uphill and 3 miles downhill. So the average speed = (15mph uphill + 30mph downhill)/2                                     = 45 mph/2                                     = 22.5 mpg So the average speed of the entire trip uphill and downhill is 22.5 mph