A shopkeeper mixes three varieties of wheat costing Rs. 30 per kg, Rs. 25 per kg and Rs. 20 per kg in the ratio 2 ∶ 1 ∶ 2 respectively. At what price should he sell the wheat mixture to earn a profit of Rs. 10 per kg?
1
Rs. 30 per kg
2
Rs. 35 per kg
3
Rs. 40 per kg
4
Rs. 45 per kg