Average Questions

The mean of 21 observations (all different) is 40. If each observation greater than the median is increased by 21, then the mean of observations will become:

The average weight of 35 apples is 50 grams. If some apples of weight 40 grams each were removed, then average weight becomes 57.5 grams. How many apples of weight 40 grams were removed?

Seven friends spent Rs 14 each on a project and the eighth friend spent Rs 21 more than the average expenditure of all eight of them. What is the amount of total money (in Rs) spent by them?

The mean of marks secured by 55 students in division A of class X is 58, 45 students of division B is 54 and that of 75 students of division C is 52. Find the mean of marks of the students of three divisions of Class X.

In a school , 391 boys and 323 girls have been divided into the largest possible equal classes , so that each class of boys numbers the same as each class of girls . What is the number of classes ?

The mode and median of the data 8, 6, 8, 7, 8, 6, 8, 7, 6 is

The standard deviation of the set {10, 10, 10, 10, 10} is

In a class of 60 students there are 30 girls. The average weight of these girls is 58 Kg and average weight of the full class is 63 kgs. What is the average weight of the boys of the class?