दूध और पानी के अनुपात 7:2 और 7:11 वाले दो घोलों को किस अनुपात में मिलाया जाए कि 5:4 अनुपात का एक घोल प्राप्त हो?

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?