The average of $50$ numbers is $38 .$ If two numbers, namely $45$ and $55$ are discarded, the average of the remaining numbers is

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 $Rs.$)

The average speed of a train in the onward journey is $25\, \%$ less than that of the return journey, The train halts for one hour on reaching the destination. The total time taken for the complete to and fro journey is $17\, hours,$ covering a distance of $800 \,km$. The speed of the train in the onward journey is (in $km/h$)

The average temperature from Monday to Thursday is $48^{\circ} C$ and from Tuesday to Friday is $52^{\circ} C$. If the temperature on Monday is $42^{\circ} C$, what was it on Friday? (in $^{\circ} C$)

The average salary per head of all the workers in a company is $Rs. \,95.$ The average salary of $15$ officers is $Rs.\, 525$ and the average salary per head of the rest is $Rs. \,85.$ Find the total number of workers in the workshop.