Disha wants to paint her room a unique 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?