Question 267467: Two planes leave an airport 30 minutes apart. The first planes flies east and the second west. After 75 minutes the planes are 700 miles apart. How fast is each flying?
I know that S X T = D. I know that the East plane flys for 1.25hrs at x speed so its distance is 1.25x. I know that the West plane flys for .75hrs at y speed so its distance is .75x. I know that if you add the two distances together you will get 700 miles. 1.25x + .75y = 700. I just don't know where to go next. Can you help?
Answer by ankor@dixie-net.com(22740)   (Show Source):
You can put this solution on YOUR website! Two planes leave an airport 30 minutes apart. The first planes flies east and the second west.
After 75 minutes the planes are 700 miles apart.
How fast is each flying?
I know that S X T = D. I know that the East plane flys for 1.25hrs at x speed so its distance is 1.25x. I know that the West plane flys for .75hrs at y speed so its distance is .75x. I know that if you add the two distances together you will get 700 miles. 1.25x + .75y = 700.
:
The problem is there are many combinations of x & y that will work here
Using your equation:
.75y = -1.25x + 700
divide by .75
y = -1.67x + 933.33
you can choose a value for x, say 300 mph, and find y = 432.33
or: x = 500, y = 98.33
an integer solution: x=399, y=267
an infinite number of solutions
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