find the answer to this problem

Question

Two planes start from Los Angeles International Airport and fly in opposite directions. The second plane starts
1
2
hour after the first plane, but its speed is 100 kilometers per hour faster. Find the airspeed of each plane if 2 hours after the first plane departs the planes are 3090 kilometers apart.
The first plane that leaves the airport travels at
kilometers per hour.
The second plane that leaves the airport travels at
kilometers per hour.

Answer 1

Distance = (Rate)(Time)

 

Let x = speed of first plane

 

Distance traveled by first plane in 2 hours = 2x

 

Speed of second plane = x+100

 

Distance traveled by second plane in 1.5 hours = 1.5(x+100)

 

So, 2x + 1.5(x+100) = 3090

 

                      3.5x = 2940

 

                          x = 840 kph

 

The first plane flies at 840 kph, while the second plane travels 940 kph.