A mixture of two types of rice costing Rs. 32 per Kg and Rs 48 per kg mixed in ratio 5 : 7 if 24 kg of mixture is replaced by 8 kg of first type of rice the ratio in the mixture becomes 6 : 7 . Find the amount of first type of rice originally.

Let original amounts be 5x kg and 7x kg. When 24 kg mixture (in 5:7 ratio) is removed, 10 kg of first type and 14 kg of second type are taken out. After adding 8 kg of first type, new amounts are (5x-10+8) = 5x-2 kg and (7x-14) kg. Given new ratio 6:7, so (5x-2)/(7x-14) = 6/7. Solving gives x=10, so original first type = 5*10 = 50 kg, which matches none of the given options.