Question 1179840
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Each of the 16 students plays a game against each of the other 15 students.  So the number of games is the number of ways of choosing 2 of the 16 students: C(16,2)=120.<br>
2*3=6 games are played at a time, so the number of "rounds" required is 120/6=20.<br>
The total elapsed time for each round is 120 seconds for the game plus 30 seconds for recording the result.  That's 150 seconds, or 2.5 minutes.  So the total time required to finish is 20(2.5) = 50 minutes.<br>