Answer:
At 5:00 p.m. the planes will be
miles apart.
Step-by-step explanation:
To solve this problem, I add a picture of the situation.
We know that speed is distance over time ⇒
(I)
The first step to solve this exercise is to graph the situation. We can draw a right triangle which vertices will be ''Tulsa'', and the planes ''A'' and ''B'' at 5:00 p.m.
In order to know the measures of the sides, we are going to calculate them using the equation (I)
Plane A leaves Tulsa at 2:00 p.m.
Therefore, at 5:00 p.m. it will have flown 3 hours ⇒
⇒


At 5:00 p.m. the distance from the plane A to Tulsa is 900 mi
Plane B leaves Tulsa at 2:30 p.m.
Therefore, at 5:00 p.m. it will have flown 2.5 hours ⇒



At 5:00 p.m. the distance from the plane B to Tulsa is 562.5 mi
Finally, we can find the distance between the plane A and the plane B using the Pythagorean theorem :




≅ 
At 5:00 p.m. the planes will be 1061.323 miles apart.