Question 1196971
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First a typical formal algebraic solution....<br>
x liters at $1.90 per liter, plus 22 liters at $2.50 per liter, yields (x+22) liters at $2.10 per liter:<br>
{{{x(1.90)+22(2.50)=(x+22)(2.10)}}}
{{{1.90x+55=2.10x+46.20}}}
{{{8.80=0.20x}}}
{{{x=8.80/0.20=44}}}<br>
ANSWER: 44 liters<br>
And then a quick and easy informal solution, if formal algebra is not required....<br>
Look at the three prices per liter -- $1.90, $2.10, and $2.50 -- (on a number line, if it helps) and observe/calculate that $2.10 is 1/3 of the way from $1.90 to $2.50.<br>
That means 1/3 of the mixture needs to be the more expensive ingredient -- i.e., there needs to be twice as much of the less expensive ingredient.<br>
Since there are 22 liters of the more expensive ingredient, there need to be 2*22 = 44 liters of the less expensive.<br>
ANSWER (again, of course): 44 liters<br>