Answer the following questions

There are three numbers in such a way that the average of the first and second numbers is 68 more than the average of the second and third number. Find the difference between first and the third number.

The average of 30 numbers is 40 and that of the other 40 numbers is 30. The average of all the numbers is-

The average monthly salary of all the employees in an industry is Rs. 12,000. The average salary of male employees is Rs. 15,000 and that of female employees is Rs. 8,000. What is the ratio of male employees to female employees?

The average age of a husband and his wife was 27 years when the child was born, the average age of the husband, the wife and new-born child is 21 years now. The present age of the child is:

The average age of a husband and wife, who were married 4 years ago, was 25 years at the time of their marriage. The average age of the family consisting of husband, wife and a child, born during the interval is 20 years today. The age of the child is:

 In a family, the average age of a father and a mother is 35 years. The average age of the father, mother and their only son is 27 years. What is the age of the son? 

The average mathematics marks of two Sections A and B of class IX 131 the annual examination is 74. The average marks of Section A is 77.5 and that of Section B is 70. The ratios of the number of students of Section A and B is:

Find the average of 1.11, 0.01, 0.101, 0.001, 0.11