Two planes start from the same airport and fly in opposite d

Two planes start from the same airport and fly in opposite directions. The second plane starts 1/2 hour after the first plane, but its speed is 80 km per hour faster. Find the groundspeed of each plane if 2 hours after the first plane departs the planes are 3200 km apart.

Solution

Make this chart

DISTANCE RATE TIME
first plane
second plane

Let the rate of the first plane be x
Let the rate of the second plane be 80 kph more or x+80
Fill those in:

DISTANCE RATE TIME
first plane x   
second plane x+80

The first plane\'s time was 2 hours
The second plane\'s time was a half hour less or 2-.5 or 1.5 hours

DISTANCE RATE TIME
first plane x 2
second plane x+80 1.5

Use D=RT to fill in the distances

DISTANCE RATE TIME
first plane 2x x 2
second plane 1.5(x+80) x+80 1.5

They are 3200 km apart, so the sum of their distances
equals 3200

2x + 1.5(x+80) = 3200

Can you solve that? If both post again asking how:

Answer: x=880

The first plane was traveling 880 kph and the second
plane was traveling 80kph faster or 960 kph.