What occurs when 100LL (blue) and 100 (green) fuels are mixed?

When 100LL (100 octane low lead, which is colored blue) and 100 (100 octane without lead, colored green) are mixed together, the resulting color is indeed purple. This is because the blue of the 100LL fuel combines with the green of the 100 fuel, producing a color that falls into the spectrum between blue and green, which is purple.

The mixing of colored fuels is specifically designed to help prevent misfueling. By observing the color of the fuel, operators can avoid mixing different types of aviation fuels that could be harmful to engine performance. In this case, recognizing the purple color indicates that both types of fuel are present, which might necessitate further action or caution, depending on the context in which the fuels are being used.

The other color options do not correctly represent the outcome of mixing these two fuels, as they do not reflect the visual result of the combination of blue and green.