The ratio of red paint to blue paint for the shade of paint is 5 / 7. For 12 quarts of blue paint, let x be the appropriate number of quarts of red paint, then 5 / 7 = x / 12 => 7x = 5(12) = 60 => x = 60 / 7 = 8.57. But Shannon mixed 8 quarts of red paint instead of 8.57 quarts of red paint. Therefore, Shannon did not mix the correct shade.Hope I helped! :) Cheers!