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?

The average age of three boys is 18 years and their age ratio is 2: 3: 4, then what is the age of the youngest boy?

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?

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?

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

Present ages of Sameer and Anand are in the ratio of 5 : 4 respectively. Three years hence, the ratio of their ages will become 11 : 9 respectively. What is Anand's present age in years?

The ratio of the present ages of Sunita and Vinita is 4 : 5. Six years hence the ratio of their ages will be 14 : 17. What will be the ratio of their ages 12 years hence?

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?