The average of 30 numbers is 15. The average of the first 18 numbers is 10 and that of the next 11 numbers is 20. The last number is

In a primary school 96 students are studying. Their average weight is 30 kg. If a student shift to another school the average weight is increased by 200 gm. Find the weight of the student who shifted from the school.

In a class, there are 30 girls and 15 boys and total average weight of class is kg. The total average weight of boys is 58 kg. Find the approximate average weight of girls. 

Some students (only boys and girls) from different schools appeared for an Olympiad exam. 20% of the boys and 15% of the girls failed the exam. The number of boys who passed the exam was 70 more than that of the girls who passed the exam'. A total of 90 students failed. Find the number of students that appeared for the exam.

The average of 100 numbers is 44. The average of these 100 numbers and 4 other new numbers is 50. The average of the four new numbers will be

The average weight of three men is increased by 4 kg when one of them, whose weight is 100 kg, is replaced by another man. What is the weight of the new man? 

The average weight of five persons sitting in a boat is 38 kg. The average weight of the boat and the persons sitting in the boat is 52kg. What is the weight of the boat?

The average age of five girls is 11. The oldest among them is 15 years old. What is the average age of the others?