List of top Quantitative Aptitude Questions on Average

In a class there are 30 girls and 20 boys and their average height is 160 cm. If the average height of girls is 150 cm, then the average height of boys is
In a survey of 80 people, 35 like tea, 40 like coffee and 15 like both. The number of people who like tea only, is
The average of 12 numbers is 15 and the average of the first two numbers is 1(D) What is the average of the remaining numbers?
A person brought a load of bags towards a weighing machine and measured the weights of the bags in a particular order. First, he weighed three bags individually, then weighed the bags taking two at a time of different combinations and lastly weighed all the three bags at a time. The recorded weight for the last measure was 203 kg. What is the average of the 7 measurers he has taken?
The total age of a group of 20 children is 160 years. If the average age of 8 of the children of the group is 12 years, find the average age of the remaining group.