20 litres of a mixture contains milk and water in the ratio 5 : 3. If 4 litres of this mixture be replaced by 4 litres of milk, the ratio of milk to water in the new mixture would be:

Tea worth Rs. 126 per kg and Rs. 135 per kg are mixed with a third variety of tea in the ratio 1 : 1 : 2. If the mixture is worth Rs. 153 per kg, what is the price of the third variety per kg ?

The average age of three boys is 25 years and their ages are in the proportion 3 : 5 : 7. The age of the youngest boy is:

The average age of three boys  is 25 years and their ages are in the proportion 3:5:7. The age of the youngest boy is

The ratio of the number of boys and girls in a college is 7 : 8. If the percentage increase in the number of boys and girls be 20% and 10% respectively. What will be the new ratio?

The present ages of Chetna and Shikha are in the ratio of 5 :7 respectively. After 7 years, their ages will be in the ratio of 11:14 respectively. What is the difference between their ages?

A truck covers a distance of 550 metres in 1 minute whereas a bus covers a distance of 33 kms in 45 minutes. The ratio of their speeds is:

A father’s age is 4 times the age of his elder son and 5 times the age of his younger son. When the elder son lived to three times his present age, then father’s age will exceed his younger son’s age by 3 yrs. What is the age of the father?

A milk vendor has 2 cans of milk. The first contains 25% water and the rest milk. The second contains 50% water. How much milk should be mixed from each of the containers so as to get 12 litres of milk such that the ratio of water of milk is 3:5?

A can contains a mixture of two liquids A and B in thye ratio 7:5. When 9 litres of mixture are drawn off and the can is filled with B, the ratio of A and B becomes 7:9. How many litres of liquid A was contained by the initially?