Question 1075678
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In the lab, Raina has two solutions that contain alcohol and is mixing them with each other. 
She uses 40 milliliters less of solution A than solution B. 
Solution {{{highlight(cross(S))}}} A is 10% alcohol and solution B is 14% alcohol. 
How many milliliters of solution B does she use, if the resulting mixture has 176 milliliters of pure alcohol?
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The solution by "josgarithmetic" is {{{highlight(W-R-O-N-G)}}}.


Below find the correct solution.


<pre>
Let V be the volume of the solution B in milliliters (the value under the question).

Then the volume of the solution A is  (V-40) milliliters, according to the condition.


The solution A contains  0.1*(V-40) milliliters of pure alcohol.

The solution B contains  0.14*V milliliters of pure alcohol.

The mixture of the solutions A and B contains  0.1*(V-40) + 0.14*V of pure alcohol.


Therefore, your equation is 

0.1*(V-40) + 0.14*V = 176.

Simplify and solve for V.


0.1*V - 0.04 + 0.14*V = 176,

0.24*V = 180  --->  V = {{{180/0.24}}} = 750.


<U>Answer</U>.  750 milliliters of the solution A.
</pre>

Solved.