A librarian purchased 60 story books for his library. But he found that he could get 4 extra books by spending Rs. 336 more and then the overall average price per book would be reduced by Re 1. The previous average price of each book was 

The average marks of the students of a class is 68. The average marks of girls in the class is 80 and that of boys is 60. What percentage of students are boys in the class?

The average of nine numbers is 50. The average of first five numbers is 54 and that of the last three numbers is 52, then the sixth number is -

An examination was conducted for five subjects where the maximum marks for each subject was 100. Scored 82,97, 88 and 91 marks in 4 subjects respectively. If his total marks were 90 percent, then how many marks did he get in fifth subjects?

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

The average weight of 8 people increase by 2.5 kg when a new person comes in place of one of them weighting 75 kg. What is the weight of the new person?

The average of five numbers is  27.  If one  number is excluded. The average becomes 25. The excluded number is

The average of 8 readings is 24.3, out of which the average of the 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?