Explanation:
Let's assume the speed of one plane is x mph and the speed of the other plane is (x + 80) mph.
When two objects are moving toward each other, their combined speed is the sum of their individual speeds. In this case, the combined speed of the two planes is:
x + (x + 80) = 2x + 80 mph
The distance traveled by both planes is 3520 miles. We can set up the equation:
Distance = Speed × Time
For the first plane:
Distance = x mph × 4 hours = 4x miles
For the second plane:
Distance = (x + 80) mph × 4 hours = 4(x + 80) miles
Since they are 3520 miles apart, their combined distances should add up to 3520 miles:
4x + 4(x + 80) = 3520
Now, let's solve for x:
4x + 4x + 320 = 3520
8x + 320 = 3520
8x = 3520 - 320
8x = 3200
x = 3200 / 8
x = 400
So, the speed of one plane is 400 mph, and the speed of the other plane is (400 + 80) = 480 mph.