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?

There are 10 balls, some of them are red and the others white. The average cost of all the balls is Rs. 28, average cost of red balls Rs. 25 and that of white balls is Rs. 30, the number of white balls is: 

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

In the first 10 overs of a cricket game, the run rate was only 7.2. What should be the average run rate in the remaining 40 overs to reach the target of 272 runs?