Question 1198805
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For Christmas, each member of a class sends the other classmates card. 
If 992 cards are exchanged, find the number of pupils in the class
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<pre>
Let the number of members be n.

Then the number of cards is n*(n-1)   (each member sends (n-1) cards to other members).


Thus an equation to find n is

    n*(n-1) = 992.


From this equation

    n^2 -n - 992 = 0

    (n-32)*(n+31) = 0

    n = 32  or  n = -31, and we choose the positive root.


<U>ANSWER</U>.  There are 32 pupils in the class.
</pre>

Solved.