GMAT Average

The average weight of 15 persons is increased by 2 kg when in place of a person having weight 70 kg another new person is included. The weight of the new person is:

A man bought 4 books for $50 each, 5 books for $60 each and 6 books for $70 each. The average cost of a book for the man is:

Two classes took the same test. One class of 20 students made an average grade of 80%, the other class of 30 students made an average grade of 70%. The average grade for all students in both classes is:

The average of 6 observations is 12. A new seventh observation is included and the new average is decreased by 1. The seventh observation is:

The average of marks obtained by 120 candidates in a certain examination is 35. If the average of passed candidates is 39 and that of the failed candidates is 15. The number of candidates who passed the examination is:

The average age of a group of 10 students is 14 years. If 5 more students join the group, the average age rises by 1 year. The average age of the new students is:

The average score of 35 students in a class is 37. If every student is given 3 grace marks, the new average of the class is:

The average of the first five prime numbers greater than 20 is:

The average monthly salary of all employees in a factory is $600 and that of 16 officers is $3000. If the average monthly salary of workers is $550, the number of workers, leaving aside officers, in the factory is

A car travels 120 km from A to B at 30 km/hour but returns the same distance at 40 km/hour. The average speed for the round trip is closest to: