<PRE><B>Question 368330</B>
A plane leaves an airport traveling at an average speed of 240km/hr. How long will it take a second plane leaving 3 hours later traveling the same route to catch up to the first plane if it travels at an average speed of 600km/hr? 

Let t = the number of hours it will take a second plane  to catch up to the   
        first plane

600t = 240*3 + 240t
360t = 720
   t = 2

It will take 2 hours for second plane  to catch up to the  first plane



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