The average of the marks of maths test of 20 students is 9. If the marks of 5 new students are 9,5,3,2,1. What is the new average marks?

The average of pappu's marks in 6 subjects is 44. If his average in 5 subjects excluding Maths is 49, how many marks he obtained in Maths?

The average of Rohan's marks in 6 subjects is 69.5. If his average in 5 subjects excluding Maths is 63.5, how many marks he obtained in Maths?

The average weight of 19 students was 50 kg. By the admission of a new student the average weight is reduced to 49.6 kg. What is the weight of the new student?

The average marks of three batches of 55, 60 and 45 students respectively is 50, 55, 60. What is the average marks of all the students?