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AURORKA [14]
3 years ago
5

One antifreeze solution is 31% alcohol and another is 15% alcohol. How much of each mixture should be added to make 28 L a solut

ion that is 27% alcohol ?
Mathematics
1 answer:
USPshnik [31]3 years ago
7 0

Let

<em>x</em> = volume of the 31% solution

<em>y</em> = volume of the 15% solution

We want a solution with a total volume of 28 L, so

<em>x</em> + <em>y</em> = 28

For each liter of either solution, there is a contribution of 0.31 L and 0.15 L of alcohol, respectively. In the resulting solution, we want a concentration of 27% alcohol, which comes out to 0.27 * 28 L = 7.56 L. So

0.31 <em>x</em> + 0.15 <em>y</em> = 7.56

The first equation says

<em>y</em> = 28 - <em>x</em>

Substitute this into the second equation and solve for <em>x</em>, then for <em>y </em>:

0.31 <em>x</em> + 0.15 (28 - <em>x</em>) = 7.56

0.31 <em>x</em> + 4.2 - 0.15 <em>x</em> = 7.56

0.16 <em>x</em> = 3.36

<em>x </em>= 21

<em>y</em> = 28 - <em>x</em>

<em>y</em> = 7

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If you would like to find 2 numbers which you can add up to get 24 and multiply to get -25, you can calculate this using the following steps:

a + b = 24 ... b = 24 - a
a * b = -25 ... a * (24 - a) = -25 ... 24 * a - a^2 = -25 ... 0 = a^2 - 24 * a - 25
0 = (a - 25) * (a + 1)
1. a = 25
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The numbers you are looking for are -1 and 25.
6 0
2 years ago
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boyakko [2]
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6 0
3 years ago
John bought an old motor bike for $ 5675 and spent $ 453 on its repair. Then he sold it in $ 7265, find out the profit he made.​
drek231 [11]

Answer:

1137

Step-by-step explanation:

5675+453

6128

Now

7265-6128

1137

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