An ostrich can run 5 mph faster than a giraffe. an ostrich can run 5 mi in the same time that a giraffe can run 4 mi. find the speed of each animal.

To answer this you can use a guess and check strategy.

You can start with having the ostrich run 10 mph. If they run 5 mile it would take 1/2 hour.

If the giraffe runs 5 miles per hour, it would run 2.5 miles in half an hour.

You can the double the speed.

If an ostrich runs 20 mph, it would take 1/4 hour to go 5 miles.

The giraffe would run 15 miles per hour so it would travel 1/4 x 15 = 3.75 miles. Closer.

Next, if the ostrich runs 25 mph, it will take 1/5 hour to go 5 miles.

If the giraffe runs 20 mph, it will go 4 miles because 1/5 x 20 = 4 miles.

The ostrich's speed is 25 mph, and the giraffe's is 20 mph.

Another way to do this is to write equivalent ratios until the speed are 5 mph apart.

4/5, 8/10, 12/15, 16/20, 20/25.

The first thing we must do in this case is to define variables.

We have then:

x: speed of the giraffe

x + 5: speed of the ostrich

By definition we have:

d = v · t

d / v = t

Where,

d: distance

v: speed

t: time

Since the time is the same then we have:

5 / (x + 5) = 4 / x

5x = 4 (x + 5)

Clearing x we have:

5x-4x = 20

x = 20 mph (speed of the giraffe)

x + 5 = 20 + 5 = 25 mph (speed of the ostrich)

Answer:

20 mph (speed of the giraffe)

25 mph (speed of the ostrich)