SOLUTION: solve. two planes travel toward each other from cities that are 780km apart at rates of 190 km/h and 200km/h. They started at the same. In how many hours will they meet?

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: solve. two planes travel toward each other from cities that are 780km apart at rates of 190 km/h and 200km/h. They started at the same. In how many hours will they meet?      Log On


   

Question 129617This question is from textbook
: solve.
two planes travel toward each other from cities that are 780km apart at rates of 190 km/h and 200km/h. They started at the same. In how many hours will they meet? This question is from textbook

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Say that the plane flying 190 km/hr covers x km when
the planes meet
The other plane covers 780+-+x km when they meet
They have both been flying for t hrs when they meet
x+=+190t
780+-+x+=+200t
There are 2 equation and 2 unknowns. It is solvable
x+=+780+-+200t
Set the x's equal to eachother
190t+=+780+-+200t
390t+=+780
t+=+2hrs
They will meet in 2 hours
check answer:
x+=+190%2A2
780+-+x+=+200%2A2
x+=+380
780+-+x+=+400
380+%2B+400+=+780
OK