Question 1030394
Two planes just took off from St. Louis, MO.  The first plane is traveling 3 times as fast as the second plane.  After traveling in the same direction for 3 hours, they are 546 miles apart.  What is the average speed of each plane?  

let speed of first plan is x km  per hours  others speed will be 3x km per hours 

relative speed of both plan (same direction )=3x-x=2x
distance=speed x time
546=2x
x=546/2 =273 kmph 
other will be 273x3= 819 kmph