<PRE><B>Question 132953</B>
Distance(d) equals Rate(r) times Time(t) or d=rt; r=d/t and t=d/r

Let t=amount of time it takes the second plane to catch the first plane  AFTER the second plane leaves.

Now we know that when the second plane leaves, the first plane will have already travelled 240*3 or 720 km.

We also know that when the two planes have travelled the same distance, the second plane will have caught up with the first plane.

Total distance first plane travels=720+240t
Total distance second plane travels=600t

And the above two distances need to be equal, so:

720+240t=600t  subtract 240t from each side
720+240t-240t=600t-240t collect like terms

720=360t  divide both sides by 360
t=2 hrs-------so 2 hrs after the second plane leaves it will catch the first plane

CK
720+240*2=600*2
720+480=1200
1200=1200


Hope this helps---ptaylor





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