Answer: The answer is:
d=220, b=300
Step-by-step explanation:
You could solve this problem using a series of equations:
d+b=520
b-80=d
How I solve this is:
If d+b=520, you could divide 520 by 2 and say that d and b's average is 260 (though that is not their value).
Then , you know that the difference between them is 80. Since the average is 260, you could add half of 80 (which is 40) and subtract the same to get 220 and 300, which, as you can see, have a difference of 80 and add up to 520. Now you have to find out which is which.
Since 80 fewer tickets were purchased at the door than before the concert (d+80=b (the second equation)), you know that the number of tickets at the door is the lesser number, making the answer:
d=220, b=300
Answer: 
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Reason:
Plot the points (0,0) and (r,s). You can place (r,s) anywhere you want.
Connect the two points mentioned and form a right triangle such that the segment from (0,0) to (r,s) is the hypotenuse of said right triangle.
The horizontal leg has a length of r-0 = r units, while the vertical leg will be 's' units.
Check out the diagram below.
We then apply the pythagorean theorem to say
where h is the hypotenuse. Solving for h gets us
. We only focus on the positive square root since a negative hypotenuse makes no sense.
Since we made the hypotenuse the segment with endpoints (r,s) and (0,0), this means the hypotenuse length and the distance are the same thing.
Therefore, the distance from (r,s) to (0,0) is 
As an alternative, you can use the distance formula to get the same answer. The distance formula is effectively the pythagorean theorem phrased a different way.
Answer:
It is proportional
Step-by-step explanation:
The pool is being filled at a constant rate.
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Answer:
26 ft square by 13 ft high
Step-by-step explanation:
The tank will have minimum surface area when opposite sides have the same total area as the square bottom. That is, their height is half their width. This makes the tank half a cube. Said cube would have a volume of ...
2·(8788 ft^3) = (26 ft)^3
The square bottom of the tank is 26 ft square, and its height is 13 ft.
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<em>Solution using derivatives</em>
If x is the side length of the square bottom, the height is 8788/x^2 and the area is ...
x^2 + 4x(8788/x^2) = x^2 +35152/x
The derivative of this is zero when area is minimized:
2x -35152/x^2 = 0
x^3 = 17576 = 26^3 . . . . . multiply by x^2/2, add 17576
x = 26
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As the attached graph shows, a graphing calculator can also provide the solution.