Question 1137197
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I will assume this is from the same person who submitted the other very similar problem at the same time....<br>
The target 40% is 1/3 of the way from the lower 30% concentration to the higher 60% concentration.  That means 1/3 of the mixture must be the higher concentration.<br>
1/3 of 60 liters is 20 liters.  So<br>
ANSWER: 20 liters of 60%; 40 liters of 30%