Arithmetic Ability
Permutations and Combinations

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Q.

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?

View Answer

Correct choice: B

Explanation:

Given total number of students in the class = 21 So each student will have 20 greeting cards to be send or receive (21 - 1(himself)) Therefore, the total number of greeting cards exchanged by the students = 20 x 21 = 420.
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