In what ratio must a shopkeeper mix two types of rice worth ₹60 per kg and ₹80 per kg, so that the average cost of the mixture is ₹75 per kg?

1 : 3 1 : 2 2 : 3 3 : 2

1 : 3

⇒ Ratio in which the rice should be mix so that avg cost of mixture is Rs. 75 is 5 : 15 = 1 : 3.