The average age of a group of person going for a movie is $20$ years. $10$ new person with an average age of $10$ years join the group on the spot due to which the average of the group becomes $18$ years. Find the number of persons initally going for the movie.

An engineering college has only four batches that contain $20,40,60$ and $80$ students respectively. The average pass percentage of these classes are $10\%,20\%,30\%$ and $40\%$respectively. Find the pass percentage of entire college.

Find the average of$f\left(x\right), g\left(x\right), h\left(x\right), d\left(x\right)$ at $x=$$1$.  $f\left(x\right)$is equal to $x^2$$+12$,$g\left(x\right)=$$15$$x^3$$-10$,$h\left(x\right)=\log$$10$$x^2$ and$d\left(x\right)=$$x^2$

The average salary of employees in TCP is, $₹20000$, the average salary of managers being $₹40000$ and the management trainees being $₹5000$. The total number of workers could be.