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## Challenge:

20 liters of 40 percent antifreeze in fuel are mixed with 40 liters of 10 percent antifreeze in fuel. The percentage of antifreeze in the new solution is:

**A-** \(15\%\)

**B-** \(20\%\)

**C-** \(25\%\)

**D-** \(30\%\)

**E-** \(35\%\)

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The correct answer is B.

The total amount of the mixture of two fuels is 60 liters. (20 liter plus 40 liters) Let’s find the total of the antifreeze.

The sum of \(40\%\) of 20 liters and \(10\%\) of 40 liters is:

\(0.40 × 20 + 0.10 × 40 = 8 + 4 = 12\)

Of 60 liters of the mixture, 12 liters are antifreeze. So, the percentage of antifreeze in the new solution is:

\(12 ÷ 60 = 0.20 = 20\%\)