James S.

asked • 02/14/17

A algebra word problem

Professor Stevens wants to mix the solution containing 13% acid with one containing an 18% acid to obtain a 50 mL solution containing 16% acid. How many milliliters of the 13% solution should the professor use?

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Mark M. answered • 02/14/17

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a represents the amount of 13% acid
50 - a represents the amount of 18% acid
 
0.13a + 0.18(50 - a) = 0.16(50)
 
Can you solve for a?
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James S.

A=20
 
i don't understand why you set up the problem like that. I'm really good at solving equations but I'm not good at setting them up. 
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02/14/17

Mark M.

The result must be 50 liters. If "a" liters comes from the 13% then "50 - a" must come from the 18% (It could be the reverse).
The percent acid from one plus the percent acid from the second must be equal to the percent in the result.
Please ask for any clarification you might want.
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02/14/17

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