The average age of six members of a family is 40 years. If the age of a guest is included, then the average age increases by 12.5%. What is the age (in years) of the guest?

A man bought 13 articles at 70 each, 15 at 60 each and 12 at 65 each. The average price per article is 

The average salary of the entire staff in an office is Rs 3200 per month. The average salary of officers is Rs 6800 and that of non-officers is Rs 2000. If the number of officers is 5, then find the number of non-officers in the office.

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?

4 boys and 3 girls spent Rs. 120 on an average, of which boys spent Rs. 150 on the average. Then the average amount spent by the girls is.

The average score of 14 students was calculated as 71. But later it was found that marks of one student were recorded as 42 instead of 56 and as 74 instead of 32 of the other. Correct average?

In a 20 over match, the required run rate to win is 7.2. If the run rate is 6 at the end of the 15th over, the required run rate to win the match is: