A farmer has a supply of chemical fertilizer of type I which contains 12% nitrogen and 8% phosphoric acid and type II fertilizer which contains 7% nitrogen and 10% phosphoric acid. After testing the soil conditions of a field, it is found that atleast 18 kg of nitrogen and 12 kg of phosphoric acid is required for a good crop. The fertilizer type I costs Rs.3.00 per kg and type II costs Rs.1.00 per kg. How many kilograms of each fertilizer should be used to meet the requirement and the cost be minimum.

A farmer has a supply of chemical fertilizer of type I which contains 12% nitrogen and 8% phosphoric acid and type II fertilizer which contains 7% nitrogen and 10% phosphoric acid. After testing the soil conditions of a field, it is found that atleast 18 kg of nitrogen and 12 kg of phosphoric acid is required for a good crop. The fertilizer type I costs Rs.3.00 per kg and type II costs Rs.1.00 per kg. How many kilograms of each fertilizer should be used to meet the requirement and the cost be minimum.