The average of marks obtained by $120$ candidates was $35.$ If the average of marks of passed candidates was $39$ and that of failed candidates was $15,$ the number of candidates who passed the examination is

$10$ years ago,the average age of all $25$ teachers of a girls' college was $45$ years. $4$ years ago,the principal retired at the age of $60$ years. One year later,a new principal aged $54$ years was recruited. Considering the principal as a teacher,what is the present average age of all $25$ teachers?

The average of $7$ consecutive numbers is $20$. The largest of these numbers is

Out of four numbers,whose average is $60$,the first one is one-fourth of the sum of the last three. The first number is

In a match,the average of runs scored by five players is $49$. If the runs scored by four players are $75, 30, 63,$ and $21$ respectively,then how many runs did the fifth player score?

Fifteen movie theatres average $600$ customers per theatre per day. If $six$ of the theatres close down but the total theatre attendance stays the same,then the average daily attendance per theatre among the remaining theatres is: