Question

If two cowboys leave a ranch at 9:00 am, how far apart will they be at 11:00 am if one travels directly north at 20 mph and the other travels directly west at 15 miles mph?

A)25 miles
B)35 miles
C)70 miles
D)50 miles
E)400 miles

Answer 1

the answer is A

if you read the question carefully and draw a diagram, you find out the two cowboys form a right angle.

you then use the Pythagorean theorem c^2 =a^2 +b^2

c^2 =20^2+15^

c^2 =625

square root both sides
c=25

Answer 2

They both traveled for two hours, so you must multiply both speeds by 2 and then add those together to get your answer. You multiply by 2 because there speed is by miles per hour, and you have 2 hours. You add the two products together because you're trying to find the distance between the two cowboys.
So, here's the actual math:
20x2=40
15x2=30
40+30=70

There are 70 miles between the two cowboys two hours after they part. So, your answer is C.