There are two groups $A$ and $B$ of a class, consisting of $42$ and $28$ students, respectively. If the average weight of group $A$ is $25 \,kg$ and that of group $B$ is $40 \,kg ,$ find the average weight of the whole class.

Out of four numbers, whose average is $60,$ the first one is one-fourth of the sum of the last three. The first number is

The average of three numbers is $28 .$ If first number is half of the second and the $3^{rd}$ number is twice the second, then the third number is?

In an examination average marks obtained by the girls of a class is $85$ and the average marks obtained by the boys of the same class is $87 .$ If the girls and boys are in the ratio $4: 5,$ average marks of the whole class $(approx.)$ is closest to

The average age of $A, B, C, D$ five years ago was $45\, years.$ By including $x$, the present average age of all the five is $49\, years.$ The present age of $x$ is (in $years$)

A cricketer has a certain average for $10$ innings. In the eleventh inning, he scored $108$ runs, thereby increasing his average by $6$ runs. His new average is