The average of three numbers is $154$. The first number is twice the second and the second number is twice the third. The first number is

The average marks of a student in four subjects is $75$. If the student obtained $80$ marks in the $5^{th}$ subject,then the new average is?

The average age of $8$ men is increased by $2$ years when $2$ of them,whose ages are $20$ years and $24$ years respectively,are replaced by $2$ women. What is the average age of these two women (in years)?

What is the average of all numbers between $100$ and $200$ which are divisible by $13$ (in $.5$)?

What is the age of a class teacher?
$I.$ There are $11$ students in the class.
$II.$ The average age of the students and the teacher is $14$ years.
$III.$ The average age of the teacher and the students is $3$ years more than that of the students.

Of the three numbers,the first is twice the second and the second is thrice the third. If the average of the three numbers is $10$,the numbers are