Carl makes baskets with bags of coffee or boxes of tea. He has 72 bags of coffee and 56 boxes of tea. He wants to put an equal n
1 answer:
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Step-by-step explanation:
We can model the annual consumption of iron by the equation
c = 900 million tons x , where
n is the number of years after 1993 and
c is the consumption for that year.
An estimate for the total consumption of iron can now be obtained by integrating this equation with respect to a dummy variable, x from 0 to n.
This equation simplifies to
C = 900 million tons x (1.025^n - 1) / ln(1.025), where
x is a dummy variable and
C is the total consumption of iron n years after 1993.
Let R be the amount of iron remaining at n years after 1993, so
R = 480 billion tons - C
R = 480 billion tons - 900 million tons x (1.025^n - 1) / ln(1.025)
We need to find the value of n when R is 0, so
0 = 480 billion tons - 900 million tons x (1.025^n - 1) / ln(1.025)
Simplify this equation to obtain
n = 107.4
So the iron will run out in the year 1993 + 107 = 2100
When , we have
and of course 3 | 6. ("3 divides 6", in case the notation is unfamiliar.)
Suppose this is true for , that
Now for , we have
so we know the left side is at least divisible by by our assumption.
It remains to show that
which is easily done with Fermat's little theorem. It says
where is prime and
is any integer. Then for any positive integer
,
Furthermore,
which goes all the way down to
So, we find that
QED