SOLUTION: Sadie and Rose run around a circular track in opposite directions. They each run at a constant rate and pass each other every 30 seconds. Sadie requires 45 seconds to go around the

Algebra ->  Rate-of-work-word-problems -> SOLUTION: Sadie and Rose run around a circular track in opposite directions. They each run at a constant rate and pass each other every 30 seconds. Sadie requires 45 seconds to go around the      Log On


   

Question 767706: Sadie and Rose run around a circular track in opposite directions. They each run at a constant rate and pass each other every 30 seconds. Sadie requires 45 seconds to go around the track once. How many seconds does it take for Rose to complete one lap?
Answer by htmentor(1343) About Me  (Show Source):
You can put this solution on YOUR website!
Sadie requires 45 s to go around the track
If they start running in opposite directions from the same point, and they meet
after 30 s, then Sadie will have gone 30/45, or 2/3 of the way around the track.
Meanwhile, Rose has run in the opposite direction and meets Sadie after 30 s.
If Sadie has run 2/3 of the way around, that means that Rose has run 1/3 of the way around.
Therefore, it will take Rose 3*30 = 90 s to complete one lap.