Aurora has a dog who loves to explore.

Question

He travels 15 miles everday. He starts his path by running and then he'll walk the way home. The dog averages 4 miles per hour faster by running. What is the dog's walking speed if he completes his entire trip in 5 hours?

Answer 1

15 miles in 5 hours is 15/5 = average speed = 3 mph

r=4+w where r is running speed and w= walking speed

3 is the average of r and w (r+w)/2 = (4+w+w)/2 = 2+w

w+2 = 3

w = 1 mph walking

r=1+4 = 5 mph running

the dog walked 2 1/2 hours and ran 2 1/2 hours

2.5 x 1 + 2.5 x 5 = 2.5x6 = 15 miles