Question 1201152
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If the speed of finding the answer is important and formal algebra is not required (as in a timed math competition), here is a quick and easy way to solve any 2-part "mixture" problem like this.<br>
15% is 2/3 of the way from 9% to 18% (picture the three percentages on a number line, if it helps)
That means 2/3 of the mixture is the higher percentage ingredient.<br>
ANSWER: 2/3 of 360 pounds, or 240 pounds, of the 18% protein ingredient; the other 120 pounds of the 9%.<br>
CHECK:
240(.18)+120(.09) = 43.2+10.8 = 54
360(.15) = 54<br>