If the diameter of the two circles is 6 units and 10 units and a centre distance of 8 units. Calculate the number of common tangents that can be drawn to both the circle.
The cost of 15 kg of groundnuts and 4 kg of cashews is Rs.7,000. The cost of 10 kg of cashews is equal to 25 kg of groundnuts. Find the cost of groundnut per kg.