A probability problem by Kshetrapal Dashottar
Probability
Level
pending
Suppose 28 objects are placed along a circle at equal distances, In how many ways can 3 objects be chosen from among them no two of the three chosen objects are adjacent not diametrically opposite?
The answer is 2268.
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1 solution
1st point can be selected in 28 ways. Total number of ways of selecting three point from which no two are adjacent = 3 C ( C2 – 24) 25 1 28 =2576 Number of ways in which points are diametrically opposite = 14 × 22 = 308 Required number of ways = 2576 – 308 = 2268