There are some friends, all less than 20 years. When paired amongst themselves they realize that the sum of their ages is a multiple of 5. If their ages are distinct prime numbers, then the number of possible pairs are: 

7 years ago, the ages of A and B were in the ratio of 4: 5 and after 7 years they would be in the ratio of 5: 6. The present age of B is-

The average age of four sisters is 7 years. If the age of the mother is include, the average is increased by 6 years. Then the age of the mother is

The multiplication of the age of Rajeev, before 5 years and after 9 years, is 15. What is the present age of Rajeev?

Two years ago, the ratio of the age (in years) at A and B was 2:3. The ratio of their respective ages, three years from now, will be 3:5. What will be the ratio of respective ages of A and B, 6 years from now?

Sum of A’s and B’s age 6 years ago is 88. A’s age 18 yrs ago is equal to B’s age 6 years ago. Find the age of A two year hence?

The ratio of present ages of Ratna and Shantanu is 5:4. After 19 years, the ratio of their ages will be 10:9. What is Ratna's present age?

A family has two grandparents, two parents and four children. Two years ago, the average age of grandparents was 72 years. A year ago, the average age of parents was 36 years. Currently, the average age of children is 12 years. What is the current average age of the family?