<PRE><B>Question 224308</B>
Two planes leave an airport at 8 a.m., one flying north at 480 km/h and the other flying south at 520 km/h. At what time will they be 3000 km apart?


Step 1.  Let x be the amount of time for the planes to be 3000 km.


Step 2.  Let distance=speed*time.


Step 3.  Let 480x be the distance traveled at 480 km/h.


Step 4.  Let 520x be the distance traveled at 520 km/h.


Step 5.  Then 480x+520x=3000 be the total distance of 3000 km traveled by both planes.


Step 6.  Solving the equation in Step 5 yields the following steps


{{{1000x=3000}}}


Divide 1000 to both sides of the equation


{{{1000x/1000=3000/1000}}}


{{{x=3}}} hours.   So 3 hours ahead of 10 a.m. is 1 p.m.


Step 7.  ANSWER:  The planes will be 3000 km at 1 p.m.


I hope the above steps were helpful. 


For free Step-By-Step Videos on Introduction to Algebra, please visit http://www.FreedomUniversity.TV/courses/IntroAlgebra or for Trigonometry visit http://www.FreedomUniversity.TV/courses/Trigonometry.


And good luck in your studies!


Respectfully,
Dr J


http://www.FreedomUniversity.TV
http://www.Facebook.com/FreedomUniversityTV
http://www.Twitter.com/FreedomUTV</PRE>