Subjects, there were 9 boys and some girls. In a test, the mean score obtained by the boys was 13 while that obtained by the girls was 15. If the overall average was 14.28, what was the total number of students in the class? 

of the three numbers, the first is 3 times the second and the third is 5 times the first. If the average of the three numbers is 57, the difference between the largest and the smallest number is: 

a, b, c, d, e, f, g are consecutive even numbers. j, k, l, m, n are consecutive odd numbers. The average of all the numbers is: 

The average marks of a student in four subjects is 75. If the student obtained 80 marks in the 5^th subject then the new average is ?

The average per day income of A, B and C is Rs. 450. If the average per day income of A and B be Rs. 400 and that of B and C be Rs. 430, the per day income of B is: 

Rohit purchased 12 kg of oranges for a total price of ₹480 and 18 kg of guavas at 30 per kg. What cost of the fruits purchased by Rohit?

The average of 12 number is 42. If a 13th number is added, then the average becomes 44. What is the 13th number?