In what ratio must wheat at ₹7.50 per kg be mixed with wheat at ₹12.40 per kg so that the mixture is worth ₹11.20 per kg?

A shopkeeper mixes two types of rice in the ratio 5 : 3, where one type costs ₹75 per kg and the other costs ₹85 per kg. Find the average price per kg of the mixture.

In what ratio (cheaper to dearer) should a grocer mix two varieties of pulses costing ₹18 and ₹22 per kg, respectively, to obtain a mixture worth ₹19.50 per kg?