The ratio of milk and water in two containers of 20 litres and 36 litres are in the ratio 3 : 7 and 7 : 5, respectively. What will be the ratio of milk and water if the two containers are mixed together?

Correct option is B

Given:
Container 1 capacity = 20 liters
Container 2 capacity = 36 liters
The ratio of milk to water in container 1 = 3 : 7
The ratio of milk to water in container 2 = 7 : 5
Solution:
Container 1:
Total parts = 3 + 7 = 10 parts
Quantity of milk in container 1 = $$\frac{3}{10}$$​ × 20 liters = 6 liters

Quantity of water in container 1 =$$\frac{7}{10}$$​ × 20 liters = 14 liters
Container 2:
Total parts = 7 + 5 = 12 parts
Quantity of milk in container 2 =$$\frac{7}{12}$$​ × 36 liters = 21 liters
Quantity of water in container 2 = ($$\frac{5}{12}$$​) × 36 liters = 15 liters
Total quantity of milk = 6 liters + 21 liters = 27 liters
Total quantity of water = 14 liters + 15 liters = 29 liters
Therefore, the ratio of milk to water when the two containers are mixed together is 27 : 29.