SOLUTION: Cory and Melissa are racing electronic cars around a circular track.  They begin at the same time going in the same direction.  Cory's car completes a revolution in 50 seconds, whi

Algebra ->  Numeric Fractions Calculators, Lesson and Practice -> SOLUTION: Cory and Melissa are racing electronic cars around a circular track.  They begin at the same time going in the same direction.  Cory's car completes a revolution in 50 seconds, whi      Log On


   

Question 569948: Cory and Melissa are racing electronic cars around a circular track.  They begin at the same time going in the same direction.  Cory's car completes a revolution in 50 seconds, while Melissa's car completes a revolution in 45 seconds.  How long will it take them before both cars reach the starting point again simultaneously?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Mark their positions and the time when
the faster car, Melissa's, makes a complete
revolution.
Melissa's 1st revolution:
Cory's is 5 sec behind, which is +5%2F50+=+1%2F10+
of a revolution for Cory
Melissa's 2nd revolution:
Cory has lost another 5 sec. He is +10%2F50+=+2%2F10+ of
a revolution behind
---------------
Melissa's 10th revolution:
Cory has lost +10%2A5+=+50+ sec, which is 1 rev for him
Melissa's 10 revolutions take +45%2A10+=+450+ sec
In 450 sec they will meet at starting point