The average weight of 15 students of a class increases by 1.5 kg when a student of 40 kg is replaced by a new student. What is the weight (in kg) of the new student?

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?

The ratio of present ages of Shankar and Mohan is 7: 8 respectively. Four year hence this ratio becomes 9: 10 respectively. What is Shankar’s present age in years?

A is 4 years younger than B. B is 12 years younger than C. 4 years hence the ratio between C and A is 9:5, Find the age of B.

The age of a mother 10 years ago was thrice the age of her son. 10 years hence, the mother's age will be twice that of 9 her son. The ratio of their present ages is :

Present age of Ram and Shyam are in the ratio of 4: 5 respectively. Five year hence the ratio of their age becomes 5:6 respectively. What is Ram’s present age?

Four years ago, the age ratio of A and B was 2: 3 and after four years this ratio will be 5: 7. What is his present age?

8 years ago, the average age of Rahul's family consisting of 6 members was 35 years. One year ago a new baby was born in this family. What will be the average age of the family four years hence?