One boy from a group of eight boys left and a new boy with a weight of 56 kg joined the group, which resulted in an average weight of 2.5 kg has increased, what is the weight of the new boy?

The average salary of all the staff in an office of a corporate house is Rs 5,000. The average salary of the officers is Rs 14,000 and that of the rest is Rs 4,000. If the total number of staff is 500, the number of officers is

A class has 90 students, of which 60 percent are girls and the rest are boys. Boys' average score in English is 30 percent higher than girls. If the average score of all students in English is 56, then what is the average score of only girls in English?

The average of the marks obtained in an examination by 8 students was 51 and by 9 other students was 68. The average marks of all 17 students was: 

The average of nine numbers in M and the average of three of these is P. If the average of remaining numbers is N, then

The average of 8 readings is 24.3, out of which the average of first two is 18.5 and that of next three is 21.2. If the sixth reading is 3 less than seventh and 8 less than eight, what is the sixth reading? 

5 number whose average is 76, the first is 3/7 times the sum of other 4. the first number is: