CAT Question 167
N persons stand on the circumference of a circle at distinct points. Each possible pair of persons, not standing next to each other, sings a two-minute song one pair after the other. If the total time taken for singing is 28 minutes, what is N?
1. 5
2. 7
3. 9
4. None of the above
August 2nd, 2011 at 9:48 am
(n*(n-3))/2 = 14
so option 2