Variety A of Dal costs Rs. 180 per kg. Variety B of Dal costs Rs. 270 per kg. Variety C of Dal was formed by mixing A and B in the ratio 3 : 2. Variety D of Dal was formed by mixing A and B in the ratio 5 : 4. C and D were mixed in a certain ratio and the resulting mixture was sold at Rs. 261 per kg at 20% profit. Find the ratio in which C and D were mixed.