The average of 8 numbers is 27. If each of the numbers is multiplied by 8, find the average of new set of numbers.

The average of 5 numbers, arranged in a row, is 309. The average of the first two of these numbers is 431 and the average of the last two of these numbers is 231.5. What is the value of the number at the center of the row?

The average of 5 consecutive natural numbers is M. If the next three natural numbers are also included, how much more than M will the average of these 8 numbers be? 

The average monthly income of x and y is 5050. The average monthly income of y and z is 6250 and the average monthly income of x and z is 5200. The monthly income of x is?

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: 

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 expenditure of a man for the first five months of a year is Rs. 5,000 and for the next seven months is Rs. 2,300 during a year. His average monthly expenditure is : 

Of the three numbers whose average is 60, the first is one-fourth of the sum of the whole number. The first number is: