Answer:
81
Step-by-step explanation:
by dividing the smallest number from the bigger number to get the last house
They are the reciprocals of each other, meaning the denominator and the numerator are in switched positions
0.0000000861 is your answer
Let's begin by listing out the information given to us:
8 am
airplane #1: x = 80870 ft, v = -450 ft/ min
airplane #2: x = 5000 ft, v = 900ft/min
1.
We must note that the airplanes are moving at a constant speed. The equation for the airplanes is given by:

2.
We equate equations 1 & 2 to get the time both airlanes will be at the same elevation. We have:

3.
The elevation at that time (when the elevations of the two airplanes are the same) is given by substituting the value of time into equations 1 & 2. We have: