On the occasion if Deepawali festival, each student in a class sends greeting cards to other. If there are 20 students in the class, find the total number of greeting cards exchanged by the students?

On the occasion of Deepawali festival, each student of a class sends greeting cards to the others. If there are 20 students in the class, then the total number of greeting cards exchanged by the students is

On the occasion of Dipawali festival each student of a class sends greeting cards to the others . If there are 20 students in the class , then the total number of greeting cards exchanged by the students is

On the occasion of Dipawali festival each student of a class sends greeting cards to others. If there are 20 students in the class, the number of cards sends by students is

On the occasion of deepawali festival each student of a class sends greetings cards to one another if the postman deliver 1640 greeting cards to the students of this class then the number of students in the class is

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

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

In a class , 45 % of students are girls, If there are 22 boys in the class, then the total number of students in the class is