If the average marks of three batches of 55, 60 and 45 students respectively is 50, 55 and 60, then the average marks of all the students is?

12 kg of rice costing 30 per kg is mixed with 8 kg of rice costing 40 per kg. The average per kg price of mixed rice is

The average weight of five persons sitting in a boat is 38 kg. The average weight of the boat and the persons sitting in the boat is 52kg. What is the weight of the boat?

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 monthly expenditure of a family for the first four months is ₹ 2570, for the next three months ₹ 2490 and for the last five months ₹3030. If the family saves ₹ 5320 during the whole year, the average monthly income of the family during the year is-

The average salary, per head, of all the workers of an institution, is Rs. 60. The average salary of 12 officers is Rs. 400; the average salary, per head, of the rest is Rs. 56. The total number of workers in the in situation is 

The average salary, per head, of all the workers of an institution is 60. The average salary of 12 officers is 400; the average salary, per head, of the rest is 56. The total number of workers in the institution is -

A man purchased 7 bags of rice at the rate of  ₹ 800 each, 8 bags of rice at ₹ 1000  each and 5 bags of rice at the rate of  ₹ 1200 each. What is the average cost of one bag of rice?