On the occasion of the Deepawali festival,eac | vedclass

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(B) In a class of $20$ students,if each student sends a card to every other student,we first consider the number of pairs that can be formed. The numb

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$2 	imes ^{20}C_2$

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(B) In a class of $20$ students,if each student sends a card to every other student,we first consider the number of pairs that can be formed. The number of ways to select $2$ students out of $20$ is given by $^{20}C_2$.Since each pair of students involves two cards being exchanged (student $A$ sends to $B$,and student $B$ sends to $A$),the total number of cards exchanged is $2 	imes ^{20}C_2$.Calculating this: $2 	imes \frac{20 	imes 19}{2 	imes 1} = 380$ cards.

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

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