How much quantity (in kg) of wheat costing Rs 84 per kg must be mixed with 81 kg of wheat costing Rs 60 per kg so that on selling the mixture at Rs 75.9 per kg, there is a gain of 15%?
A mixture contains liquid A and liquid B in the ratio of 5 : 4. If 2 litres of liquid B is added to it, then the ratio of liquid A and liquid B becomes 7 : 6. What is the quantity (in litres) of liquid A in the mixture?