Question

A zebra runs 15 miles per hour faster than an elephant. The zebra runs 8 miles in

the same time that an elephant runs 5 miles. Write and solve an equation to
calculate the speed of each animal.

Answer 1

elephant: 25 mph; zebra: 40 mph

Explanation:

The time required is the same in each case, so we need to set up an equation of the form distance1/speed1 = distance2/speed2:

8 miles 5 miles

------------- = time = -------------

speedz speede

From this we get:

8 5

------------------ = -------------------

speede + 15 speede

Cross multiplying, we get: 8(speed e) = 5(speede) + 75, or

3(speede) = 75, or

speede = 25 mph

Then speedz = 25 mph + 15 mph = 40 mph = speedz