Question 1169472
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Here is a quick and easy alternative to the standard algebraic solution method shown by the other tutors.  It can be used on any of a wide number of different types of 2-part mixture problems.<br>
Picture the problem as starting with some 4% alcohol and adding some 100% alcohol, stopping when the mixture is 8% alcohol.<br>
In stopping at 8%, what fraction of the way from 4% to 100% did you go?<br>
Picturing the three percentages on a number line, observe that 8 is 4/96 = 1/24 of the way from 4 to 100.<br>
That means 1/24 of the total mixture is the 100% alcohol.<br>
ANSWER: 1/24 of the total 480ml, or 20ml, is the 100% alcohol; the other 460ml is the 4% alcohol.<br>
CHECK:
20(1.00)+460(0.04) = 20+18.4 = 38.4
480(0.08) = 38.4<br>