$A, B, C$ and $D$ are four consecutive odd numbers and their average is $42$. What is the product of $B$ and $D$?

Nine friends have a dinner in a hotel. Eight of them spent $Rs. 12$ each on their meals and the ninth spent $Rs. 16$ more than the average expenditure of all the nine. Find out the total money in $Rs.$ spent by them?

Roshan bought $5$ pants at $Rs. 25$ each,$10$ shirts at $Rs. 50$ each,and $15$ ties at $Rs. 35$ each. Find the average price of all the articles in $Rs.$

Of the three numbers whose average is $60$,the first is one-fourth of the sum of the others. The first number is

$A$ man spends $Rs. 1800$ monthly on an average for the first four months and $Rs. 2000$ monthly for the next eight months and saves $Rs. 5600$ a year. His average monthly income is (in $Rs.$)

In an examination,out of $20$ students in a class,in Mathematics $2$ students scored $100$ marks,$3$ students scored $0$,and the average marks for the rest of the students was $40$. What is the average mark of the whole class? (in marks)