A mathematics teacher calculated the total marks obtained by 35 students of 8th class . The average marks of the students were 72. But 36 marks for Reena was calculated in place of 86 obtained by her. What was the correct average of all the students? 

The average age of 6 members of a family is 25 years. If the youngest member of the family is 15 years, old then what was the average age (in years) of the family at the time of the birth of the youngest members?

What decimal of a week is an hour? 

The average of a collection of 20 measurements was calculated to be 56 cm . But later it was found that a mistake had occurred in one of the measurements which was recorded as 64 cm, but should have been 61 cm. The correct average must be: 

The average weight of A B and C is 50 kg . if the average weight of A and B be 48 kg and that of B and C be 45 kg , then find the weight of B ?

In an exam of 100 marks, the average marks of a class of 40 students are 76. If the top 3 scorers of the class leave, the average score falls “down by 1. If the other two toppers except “the highest topper scored not more than 85. “then what is the minimum score the topper can score?

The average of ten numbers is 72. The average of the first four numbers is 69 and that of the next three number is 74. The 8^th number is 6 more than the 9^th number and 12 more than the 10^th number. What is the average of the 8^th and 9^th numbers?

There are 1600 students in a college, whose average weight is 50 kg. If average weight of boys is 54 kg. and average weight of girls is 38 kg. Then find the number of girls in the school.