The average age of students of a class is $15.8 \text{ years}$. The average age of boys in the class is $16.4 \text{ years}$ and that of the girls is $15.4 \text{ years}$. The ratio of the number of boys to the number of girls in the class is:

The average of $25$ consecutive odd integers is $55$. The highest of these integers is

The average of three numbers is $28$. If the first number is half of the second and the third number is twice the second,then the third number is?

Average rainfall on Monday,Tuesday,Wednesday and Thursday is $420.5\, cm$ and average on Tuesday,Wednesday,Thursday and Friday is $440.5\, cm$. If the ratio of rainfall for Monday and Friday is $20:21$,find the rainfall in $cm$ on Monday and Friday.

$16$ children are to be divided into two groups $A$ and $B$ of $10$ and $6$ children,respectively. The average marks obtained by the children of group $A$ is $75$ and that of all the children is $76$. Then,the average marks of the children of group $B$ is?

Eleven years earlier,the average age of a family of $4$ members was $28 \, \text{years}$. Now,the average age of the same family with $6$ members is still the same,even though $2$ children were born in this period. If they belong to the same parents and the age of the first child at the time of the birth of the younger child was the same as the total number of family members just after the birth of the youngest member,then what is the present age of the youngest member of the family in years?