If the average of $m$ numbers is $n^{2}$ and that of $n$ numbers is $m^{2},$ then the average of $( m + n )$ numbers is
$\frac{m}{n}$
$m+n$
$m n$
$m-n$
A man spends on an average $Rs.\, 269.47$ for the first $7 \,months$ and $Rs.\, 281.05$ for the next $5\, months.$ Find out his monthly salary if he saved $Rs.\,308.46$ during the $year.$ (in $Rs.$)
The average salary of all the workers in a workshop is $Rs.\,8000.$ The average salary of $7$ technicians is $Rs.\, 12000$ and the average salary of the rest is $Rs.\,6000 .$ The total number of workers in the workshop is
The average score of Sachin after $25$ innings is $46$ runs per innings. If after the $26^{th}$ innings, his average runs increased by $2$ runs, then what is his score in the $26^{\text {th }}$ innings?
The mean of $11$ numbers is $35 .$ If the mean of first $6$ numbers is $32$ and that of the last $6$ numbers is $37,$ then find the sixth number.
A professional institute's total expenditure on students for a particular course is partly fixed and partly varies linearly with the number of students. The average expense per student is $Rs.\,615$ when there are $24$ students and $Rs.\,465$ when there are $40$ students. What is the average expense when there are $60$ students ? (in $Rs.$)