The average weight of 5 persons sitting in a boat is 38 kg. The average weight of the boat and the persons sitting in the boat is 52 kg. What is the weight of the boat?

The average of 8 readings is 24.3, out of which the average of the 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 average of nine numbers is 50. The average of first five numbers is 54 and that of the last three numbers is 52, then the sixth number is -

The average of three numbers is 40. The first number is twice the second and the second one is thrice the third number. The difference between the largest and the smallest numbers is

If (a + b): (b + c): (c + a) = 5: 6: 9 and a + b + c = 10. What is the value of c?

Average age of x students in a group is 20. When 4 new students are admitted with a age of 7.5 years each, then the average is decreased by 5. What is the value of x?

The present age of a father is 3 years more than three times the age of his son. Three years hence, father's age will be 10 years more than twice the age of the son. The father's age is: 

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 :