The average monthly salary of 660 workers in a factory is Rs. 380. The average monthly salary of officers is Rs. 2100 an…

From a class of 42 boys, a boy aged 10 years goes away and in his place, a new boy is admitted. If on account of this ch…

The mean of 5 observations is 60, the mean of 10 observations is 30 and the mean of 15 observations is 20. The mean of a…

The average expenditure of a man for the first five months of a year is Rs. 5000 and for the next seven months it is Rs.…

The average age of three boys is 15 years. If their ages are in ratio 3 : 5 : 7, the age of the youngest boy is

The arithmetic mean of 15 numbers is 41.4. Then the sum of these numbers is-

In Arun's opinion, his weight is greater than 65 kg but less than 72 kg. His brother doest not agree with Arun and he th…

The average age of a family of 10 members is 20 years. If the age of the youngest member of the family is 10 years, then…