Give stream of consciousness and then the final answer. There are 9 cities numbered 1 to 9.From how many cities the flight can start so as to reach the city 8 either directly or indirectly such that the path formed is divisible by 3.
Options:
(A) 7
(B) 8
(C) 9
(D) 10
(E) 11
Start from 1: 1368, Start from 2: 2358, Start from 3: 378, Start from 4: 48, Start from 5: 528, Start from 6: 678, Start from 7: 78, Why start from 8???, Start from 9: 918. So flights can start from all 8 other cities.
The final answer: (B).