If the average of the ages of Rakesh and Mohan is $15,$ average of the ages of Mohan and Ramesh is $12$ and the average of the ages of Rakesh and Ramesh is $13,$ then the age of Mohan, is?

In a family, the average age of a father and a mother is $35\, years.$ The average age of the father, mother and their only son is $27\, years.$ What is the age of the son ? (in $years$)

In a class, the average height of $35$ girls was measured $160 \,cm$. Later, on it was discovered that height of one of the girls was misread as $144\, cm ,$ while her actual height was $104 \,cm.$ What was the actual average height of the girls in the class? (in $cm$) (rounded off to two digits after decimal)

The average marks of $40$ students in an examination was $25 .$ It was later found that the marks of one student had been wrongly entered as $73$ instead of $37.$ What is the value of correct average

The average of four consecutive odd numbers is $40 .$ What is the largest number?

The average of $10$ mumbers is $7 .$ What will be the new average if each of the numbers is multiplied by $8 \,?$