The average marks of $40$ students in an English exam is $72 .$ Later it is found that three marks $64 , 62$ and $84$ were wrongly entered as $68,65$ and $73.$ The average after mistakes were rectified is

Last year, $5$ companies had an average of $16$ non working days each, and $2$ companies had $5$ fewer non working days each. What was the average number of non working days given by the same companies this $year$ ?

The average age of three boys is $15$ $year.$ If the ratio of their ages is $3:5: 7,$ what is the age of the oldest boy in $year$?

The average of $25$ results is $20 .$ the average of first $12$ results is $15$ and that of the last $12$ results is $18 .$ Then, the $13^{ th}$ results is

The average marks of a class of $35$ children is $35 .$ The marks of one of the students, who got $35,$ was incorrectly entered as $65 .$ What is the correct average of the class?

The average of consecutive numbers is $n .$ If the next two consecutive numbers are also included, the average of the five numbers will