SOLUTION: On Saturday morning John walked for 2 hours and then ran for 30 minutes. Is he ran twice as fast as he walked and he covered 12 miles altogether, how fast did he walk

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Question 188953: On Saturday morning John walked for 2 hours and then ran for 30 minutes. Is he ran twice as fast as he walked and he covered 12 miles altogether, how fast did he walk

Answer by jonvaliente(64) About Me  (Show Source):
You can put this solution on YOUR website!
Let w = John's speed walking
r = John's speed running

Since distance = speed * time, then:
2w + (0.5)r = 12
r = 2w
Substituting 2w for r, we get
2w + (0.5)(2w)=12
3w = 12
w=4
r = 2(4)
r = 8
Therefore, John walks at 4mph and runs at 8mph