Amy wants to travel from elm town to lakeside at an average speed of 50 miles per hour. She travels half the distance and finds out her average speed has been on 25 miles per hour. How fast must she drive for the rest of the trip to average 50 miles per H our for the whole trip.?

Question

I say 75 miles per hour

Answer 1

let's call the distance d

so the desired time for Amy's trip is ... d / 50

her time at the halfway point is ... (d / 2) / 25 , which equals ... d / 50

she has run out of time to achieve her desired average speed