Three science classes A, B and C take a Science test. The average score of class A is 83. The average score of class B is 76. The average score of class C is 85. The average score of class A and B is 79 and average score of class B and C is 81. Then the average score of classes A, B and C is

A mathematics teacher calculated the total marks obtained by 35 students of 8th class . The average marks of the students were 72. But 36 marks for Reena was calculated in place of 86 obtained by her. What was the correct average of all the students? 

In an exam of 100 marks, the average marks of a class of 40 students are 76. If the top 3 scorers of the class leave, the average score falls “down by 1. If the other two toppers except “the highest topper scored not more than 85. “then what is the minimum score the topper can score?

The total number of students in sections A and B of a class is 72. The ratio of the number of students in A and B is 7 :5 . The average weight (in kg) of the students in section B is 20% more than that of the students in section A. If the average weight of all the students in the class is 52 kg, then what is the average weight (in kg) of the students in section B?

The average weight of A, B and C is 45 kg. If the average weight of A and B be 40 kg and that of B and C be 43 kg, then the weight (in kg) of B is 

The total marks obtained by Abhishek in Zoology, Botany and Chemistry together is 180 more than the marks obtained by him is botany. What are the average marks obtained by him is zoology and Chemistry together?

The average of 19 numbers is 24. If each number is multiplied by 3, what is the new average?

While purchasing one item costing Rs.400, one has to pay sales tax at 7 % and on another costing Rs. 6400, the sales tax was 9%. The percentage of sales tax one has to pay, taking these items together on an average is: