The average of marks scored by the students of a class is 68. The average of marks of the girls in the class is 80 and that of the boys is 60. What is the percentage of boys in the class? 

A company produces an average of 4000 items per month for the first 3 months. How much items, it must produce on an average per month over the next 9 months to get average of 4375 items per month over the whole year? 

The average weight of 5 men is increased by 4 kg. If one of them who weigh 121 kg is replaced by another man, then what is the weight of the new man? 

The average marks of 42 students in an examination, were 64. Later it was found that the marks of three students were misread as 72, 58 and 44 instead of the actual marks 64, 42 and 26 respectively. What are the correct average marks?

What is the age of A in a group of 6 students – A, B, C, D, E and F whose average age is 16 years?
Statement I: Total age of B and D is 30 years
Statement II: Total age of E and F is 31 years.
Statement III: Total age of A is 10 years.

In a class of 50 students there are 27 girls. The average weight of these girls is 45 kg and average weight of the full class is 49.6 kgs. What is the average weight of the boys of the class?

A car reaches its destination in time when moving with an average speed of 45 km/hr. But when it is moving at 30 km/hr, it is late by 10 minutes. Find the total distance of the journey?

The average of five numbers is  27.  If one  number is excluded. The average becomes 25. The excluded number is