Disha wants to paint her room brown. For that she uses a certain violet paint which contains $30\%$  blue pigment and $70\%$   red pigment by weight. She mixes that violet paint with a certain green paint which contains $50\%$   blue pigment and $50\%$   yellow pigment. When these paints are mixed to produce the brown paint which she uses, it contains $40\%$   blue pigment. If the brown paint weighs 10 grams, then the red pigment contributes how many grams of that weight?