If a dairy mixes cow’s milk which contains 10% fat with buffalo’s milk which contains 20% fat, then the resulting mixture has fat (120/7) % of fat. In what ratio was the cow’s milk mixed with buffalo’s milk?

If a dairy mixes cow’s milk which contains 10% fat with buffalo’s milk which contains 20% fat, then the resulting mixture has fat (120/7) % of fat. In what ratio was the cow’s milk mixed with buffalo’s milk? Correct Answer 2 : 5

Let the amount of cow milk be x and buffalo milk be 1.

⇒ Amount of fat added = 10% of x + 20% of 1 = 0.1x + 0.2

⇒ Total amount of milk = 1 + x

⇒ Net fat % = {(0.1x + 0.2) / (1 + x)} × 100 = 120/7

⇒ (0.1x + 0.2) / (1 + x) = 6/35

⇒ 3.5x + 7 = 6 + 6x

⇒ x = 1/2.5 = 2/5

∴ Required ratio = 2 : 5

Related Questions

Jar A comprises a mixture of milk and water in the ratio of 3 : 2 respectively. Another mixture of milk and water is added to jar A and the ratio of milk and water in the resultant mixture changes. What was the initial quantity of mixture present in Jar A? I. The ratio of milk and water in the mixture that was added to Jar A was 2 : 1 respectively. II. The ratio of the new quantities of milk and water in Jar A was 8 : 5 respectively. The quantity of water in the mixture added to jar A was 6 litre.