SOLUTION: At 7:00 a.m. Joe starts jogging at 6 mph. At 7:10 a.m. Ken starts off after him. How fast must Ken run in order to overtake him at 7:30 a.m.

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Question 116080: At 7:00 a.m. Joe starts jogging at 6 mph. At 7:10 a.m. Ken starts off after him. How fast must Ken run in order to overtake him at 7:30 a.m.
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
At 7:00 a.m. Joe starts jogging at 6 mph. At 7:10 a.m. Ken starts off after him. How fast must Ken run in order to overtake him at 7:30 a.m.
:
Since we are dealing in mph,
Change J's run time to hrs, 30 min = 1%2F2 hr
Change K's run time to hrs, 20 min = 1%2F3hr
:
Let s = Ken's speed (mph) to overtake Joe at 7:30
:
When K overtakes J they will have traveled the same distance
Write a distance equation: Dist = time * speed
:
K's dist = J's dist
1%2F3s = 1%2F2(6)
:
Cross multiply:
2s = 3(6)
s = 18%2F2
s = 9 mph for K to catch up with J at 7:30
:
:
Check solution by finding that their distances are, indeed, equal:
1%2F2(6) = 3 mi
1%2F3(9) = 3 mi