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Janene and Emily plan to go on a marathon training run. Emily arrives late, so Janene starts running 16 minutes before Emily. Janene runs at an average rate of 9 minutes per mile, and Emily runs at an average rate of 8 1/4 minutes per mile. Assuming that both girls started at the same location and ran the same route, how many minutes will Emily take to catch up to Janene?

 Jul 27, 2015

Best Answer 

 #1
avatar+128456 
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If Janene runs 1 mile in 9 minutes, each minute, she runs (1/9) of a mile.

 

And if Emiliy runs 1 mile in 8.25 minutes, then each minute she runs (1/8.25) = (4/33) of a mile

 

Then, in each minute, the amount of ground that Emily "makes up" on Janene = (4/33) - (1/9) = 1/99 mi

 

And, if Janene runs for 16 minutes before Emily arrives, she is 16(1/9) = 16/9 miles ahead of Emily when Emily starts.

 

So.....the time it will take Emily to catch Janene is given by (1/99)M = 16/9  where M is the time in minutes.

 

Multiply both sides by 99  and we have  M = (99/9)*16 = 11 * 16  = 176 minutes  for Emily to catch Janene

 

 

  

 Jul 27, 2015
 #1
avatar+128456 
+6
Best Answer

If Janene runs 1 mile in 9 minutes, each minute, she runs (1/9) of a mile.

 

And if Emiliy runs 1 mile in 8.25 minutes, then each minute she runs (1/8.25) = (4/33) of a mile

 

Then, in each minute, the amount of ground that Emily "makes up" on Janene = (4/33) - (1/9) = 1/99 mi

 

And, if Janene runs for 16 minutes before Emily arrives, she is 16(1/9) = 16/9 miles ahead of Emily when Emily starts.

 

So.....the time it will take Emily to catch Janene is given by (1/99)M = 16/9  where M is the time in minutes.

 

Multiply both sides by 99  and we have  M = (99/9)*16 = 11 * 16  = 176 minutes  for Emily to catch Janene

 

 

  

CPhill Jul 27, 2015

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