Find the average of all the numbers between $6$ and $34$ which are divisible by $5$

The average age of students of a class is $15.8$ $years.$ The average age of boys in the class is $16.4\, years$ and that of the girls is $15.4 \,years.$ The ratio of the number of boys to the number of girls in the class is

The bowling average of a cricketer was $12.4 .$ He improves his bowling average by $0.2$ points, when he takes $5$ wickets for $26$ runs in his last match. The number of wickets taken by him before the last match Was?

Find average of all prime numbers between $60$ and $90.$

Of the three numbers, second is twice the first and is also thrice the third. If the average of the three numbers is $44,$ the largest number is

There were $35$ students in a hostel. If the number of students is increased by $7,$ the expenditure on food increase by $Rs. \,42$ per $day$ while the average expenditure of students is reduced by $Rs.\, 1.$ What was the initial expenditure on food per day? (in $Rs.$)