An alloy contains zinc, copper and tin in the ratio 2:3:1 and another contains copper, tin and lead in the ratio 5:4:3. If equal weights of both alloys are melted together to form a third alloy, then the weight of lead per kg in new alloy will be:

In a 729 litres mixture of milk and water, the ratio of milk to water is 7:2. to get a new mixture containing milk and water in the ratio 7:3, the amount of water to be added is: