Question

On the occasion of New Year, each student of a class sends greeting cards to the others. If there are 21 students in the class, what is the total number of greeting cards exchanged by the students?
A) 380
B) 420
C) 441
D) 400

Answer 1

Its a permutation and combination question. So basically 1 student can send 20 cards. So 21 students can give 20×21 cards i.e. 420 cards. Hope I am right.... Cheers mate.

Answer 2

Answer:

420

Step-by-step explanation:

no. of students = 21

1st student can exchange with the second student and second with third and so on.....

So each student will have 20 greeting cards to be send or receive

i.e., (21 - 1(himself))

so total number of greeting cards exchanged = 21 x 20

                                                                             =  420

hence option B is the answer.