SOLUTION: How many quarters will fit in a can that is 25.5 inches circumference and 8.5 inches tall?

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Question 1204675: How many quarters will fit in a can that is 25.5 inches circumference and 8.5 inches tall?
Found 6 solutions by greenestamps, josgarithmetic, Alan3354, Edwin McCravy, ikleyn, math_tutor2020:
Answer by greenestamps(13209) About Me  (Show Source):
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It is not possible even to begin working on this problem without knowing the dimensions of the quarters. And there would likely by a small variation in the dimensions of those quarters.

And even if we knew those dimensions, we could only get an approximate answer, because it is impossible to know exactly how the quarters would be stacked in the can.


Answer by josgarithmetic(39630) About Me  (Show Source):
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Need to know how to calculate or to test for packing density first.

Answer by Alan3354(69443) About Me  (Show Source):
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If you melt the quarters, you can get more of them in.
But, that might be illegal.

Answer by Edwin McCravy(20064) About Me  (Show Source):
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Let's assume the quarters are all uncirculated, in tall cylindrical 
stacks, standing vertically in the can.

By Googling, I have found these facts:

1. The official diameter of a quarter is 0.955 inches.
2. The official thickness of a quarter is 0.069 inches.
3. The maximum number of non-overlapping smaller circles of 
diameter d that will fit inside a larger circle of diameter D 
is the integer part of D%5E2%2Fd%5E2 

Since the circumference of the can is 25.5 inches, its diameter is

D=25.5%2Fpi = 8.116902098 inches.  

The diameter of a quarter is 0.955 inches,

so using the formula,

8.116902098%5E2%2F0.955%5E2=+72.2393571.

So 72 stacks of quarters can be placed in the can.  

Now since the can is 8.5 inches tall, and a quarter has thickness 0.069 inches,
we see how many quarters are in each stack. 

8.5%2F0.069=123.1884058

So there are 123 quarters in each stack.  So we multiply that by 72 stacks
and get 8856 quarters. [worth $2214]

Edwin

Answer by ikleyn(52887) About Me  (Show Source):
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.
How many quarters will fit in a can that is 25.5 inches circumference and 8.5 inches tall?
~~~~~~~~~~~~~~~~~~~~~~~~~~~

Let's consider these quarters packed in vertical stacks inside the can.


The diameter of the can     is  D = 25.5%2F3.14159 = 8.117 inches (rounded).

The diameter of a quarter   is  d = 0.955 inches (an official info).


D%2Fd = 8.117%2F0.955 = 8.5.


So, the problem is reduced to this question


    +---------------------------------------------------------------+
    |        how many circles of radius 1 unit can be placed        |
    |     in the circle of radius 8.5 units without overlapping     |
    +---------------------------------------------------------------+


In the Internet, there is web-site  http://www.packomania.com/  and the calculator there 
(free of charge, for common use).


 +----------------------------------------------------------------------------+
 | It easily determines the MAXIMUM possible solution for such placing (!!!). |
 |  and even shows you a final diagram  (which is just a fantastic service)   |
 +----------------------------------------------------------------------------+


In our case, 57 circles are possible to place without overlapping.


The number of quarters in each stack is  8.5%2F0.069 = 123  (rounded to the closest smaller integer).


So, the  ANSWER  to the problem's question, using this conception, is  

                           57*123 = 7011.

Solved.

-------------------

What is remarkable and amazing,  this solution  (in the frame of this conception)
is exact and precise - - - not approximate  ( ! )



Answer by math_tutor2020(3817) About Me  (Show Source):
You can put this solution on YOUR website!

For anyone curious, info about the quarter can be found here
https://www.usmint.gov/coins/coin-medal-programs/circulating-coins/quarter
Scroll down to the "Specifications" section.

The two pieces of info we need are
Diameter = 0.955 inches
Thickness = 1.75 mm which converts to 0.06889764 inches approximately.

It's unfortunate that the teacher or textbook author did not state these bits of info in the instructions.