$12 \%$ of Kaushal's monthly salary is equal to $16 \%$ of Nandini's monthly salary. Suresh's monthly salary is half that of Nandini's monthly salary. If Suresh's annual salary is $Rs.\,1.08$ $lacs.$ What is Kaushal's monthly salary? (in $Rs.$)

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 $Rs.$)

Out of $30$ teachers of a school, a teacher of age $60$ $years$ retired. In his place another teacher of age $30$ $years$ was appointed. As a result, the mean age of the teachers will

In a set of prime and composite numbers, the composite numbers are twice the number of prime number and the average of all the numbers of the set is $9 .$ If the number of prime numbers and composite numbers are exchanged then the average of the set of numbers is increased by $2 .$ If during the exchange of the numbers the average of the prime numbers and composite numbers individually remained constant, then the ratio of the average of composite numbers to the average of prime numbers (initially) was

The average price of $80$ computers in an electronic shop is $Rs.\, 30,000 .$ If the highest and lowest price computers are sold out then the average price of the remaining $78$ computers is $Rs.\, 29,500 .$ The cost of the highest price computer is $Rs.\, 80,000 .$ The cost of lowest price computer is in $Rs.$ 

The average of $7$ numbers is $5 .$ If the average of first six of these numbers is $4,$ the seventh number is