Question

You are able to bike 20 miles in the same time that your friend ran 3 miles. If your speed was 5 miles per hour faster on average than your friend's speed, what was the average speed of your friend? ​

Answer 1

Explanation:

Givens

d = 20 for the bike

d1 = 3 for the person

rate of person = r

rate of bike = r + 5

Formula

d = r*t; t = d/r

Solution

t is the same for both

20/(r + 5) = 3/r Cross multiply

20*r = 3*(r + 5) Remove the brackets.

20*r = 3r + 15 Subtract 3r from both sides.

20r - 3r = 3r - 3r + 15 Combine

17r = 15 Divide by 17

r = 15/17

r = 0.8824 miles per hour running