The average of the test scores of a class of $'m'$ students is $70$ and that of $'n'$ students is $91.$ When the scores of both the classes are combined, the average is $80 .$ What is $n / m$ ?
$\frac{11}{10}$
$\frac{13}{10}$
$\frac{10}{13}$
$\frac{10}{11}$
The average speed of a cyclist who covers first, second and third km at $20,16$ and $12\, km / hr$ respectively ( in $km / hr )$ is
There are $6$ consecutive odd numbers in increasing order. The difference between the average of the squares of the first $4$ numbers and the last four numbers is $64 .$ If the sum of the squares of the first and the last element (i.e., odd numbers) is $178 ,$ then the average of all the six numbers is
The average expenditure of a man for the first five months is $Rs.\, 3600$ and for next seven months it is $Rs.\, 3900 .$ If he saves $Rs.\, 8700$ during the $year,$ his average income per $month$ is (in $Rs.$)
The average of certain first consecutive even number is $101.$ Find their sum?
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 $Rs.$)