An artist has three 100ml tubes of paint: one red, one yellow and one blue. Mixing equal quantities of red and yellow gives orange, mixing equal quantities of red and blue gives purple, mixing equal quantities of yellow and blue gives green, and mixing equal quantities of red, yellow and blue gives brown. The design of a small mural needs 30% of brown and 20% of red, as well as 10% of each of blue, yellow, orange, purple and green.