What is the average of first $7$ multiples of $7\, ?$
$7$
$14$
$21$
$28$
The average of nine numbers is $50.$ The average of the first five numbers is $54$ and that of the last three numbers is $52 .$ Then the sixth number is?
The average of a batsman after $25$ innings was $56$ runs per innings. If after the $26^{\text {th }}$ inning his average increased by $2$ runs, then find his score in the $26^{\text {th }}$ inning?
The mean weight of $150$ students in a class is $60 \,kg.$ The mean weight of boys is $70\, kg$ and that of girls is $55 \,kg$. What is the number of boys in the class?
The average of $12$ results is $15,$ and the average of the first two is $14.$ What is the average of the rest?
The average of first $46$ natural number is