I need help understanding the problems and steps

Question

Two planes leave San Diego heading in opposite directions. The plane traveling west can travel 50 mph faster than the plane heading east. After 4 hours the plans are 1,000 miles apart. How far did each plane travel 

Answer 1

1. x = speed of the eastbound plane (mph)
2. x + 50 = speed of the westbound plane (mph)

In 4 hours:

1. Eastbound distance = 4x miles
2. Westbound distance = 4(x + 50) miles

Total distance apart is 1000 miles: 4x + 4(x + 50) = 1000 4x + 4x + 200 = 1000 8x = 800 x = 100 mph (eastbound speed)

1. Eastbound distance = 4 * 100 = 400 miles
2. Westbound speed = 100 + 50 = 150 mph
3. Westbound distance = 4 * 150 = 600 miles

Answer: The eastbound plane traveled 400 miles, and the westbound plane traveled 600 miles.