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? 

The mean of 14 observations is 11. One more observation is included and the new mean becomes 12. The  observation is

The average age of students in a class is 15.8 years. The average age of boys in the class is 16.4 years and that of the girls is 15.4 years. The ratio of the number of boys to the number of girls in the class is:

In a class of 66 students there are 33 girls. The average weight of these girls is 61 Kg and average weight of the full class is 66 kgs. What is the average weight of the boys of the class?

The average weight of A B and C is 50 kg . if the average weight of A and B be 48 kg and that of B and C be 45 kg , then find the weight of B ?

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

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

If the average marks obtained by Balu, Benjamin and Babur is 80 and the average marks of Benjamin and Babur is 83, find marks obtained by Balu.