Question 1142753
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15% is 5/8 of the way from 10% to 18%.<br>
That means 5/8 of the total should be the 18% antifreeze.<br>
Given that the 7.5L of the 18% antifreeze is 5/8 of the total, use any of a number of methods to determine that we need 4.5L of the 10% antifreeze.<br>
ANSWER: 4.5L of the 10% antifreeze should be mixed with the 7.5L of 18% antifreeze.