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| Question 963617:  Per, Paul, and Mary are starting at the same time walking around a circular track in the same direction. Peter takes 1/2 hr to walk around the track. Paul takes 5/12 hour and Mary takes 1/3 hour. How many times will each person go around the track before all three meet again at the startling line?
 Answer by ankor@dixie-net.com(22740)
      (Show Source): 
You can put this solution on YOUR website! Per, Paul, and Mary are starting at the same time walking around a circular track in the same direction. Peter takes 1/2 hr to walk around the track.
 Paul takes 5/12 hour and
 Mary takes 1/3 hour.
 How many times will each person go around the track before all three meet again at the startling line?
 ;
 Let's convert this to minutes, get rid of those annoying fractions!
 :
 Peter: 30 min
 Paul: 25 min
 Mary: 20 min
 :
 Find the least common multiple using prime factoring
 30: 2*3*5
 25: 5 * 5
 20: 2*2*5
 LCM: 2*2*3*5*5 = 300 min, all at the starting line again
 then
 Peter: 300/30 = 10 times
 Paul: 300/25 = 12 time
 Mary: 300/20 = 15 times
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