On a new year day every student of a class sends a card to every other student. The postman delivers `600` cards. The number of students in the class are

On a new year day every student of a class sends a card to every other student. The post man delivers 600 cards. How many students are there in the class?

800 chocolates were distributed among the students of a class. East student got twice as many chocolates as the number of students in the class. The number of students in the class was:

In a class, there are 45 students. On a new year eve, every student sends one greeting card to each of the other students. How many greeting cards were exchanged in all?

On the event of new year each student of class XI sends cards to his classmates. If there are 40 students in the class number of cards exchanged during the process is

The ages of the students of a class form an A.P. whose common difference is 4 months. If the youngest student is 8 years old and the sum of the ages of all the students of the class is 168 years, find the number of students in the class.