Permutation and CombinationHard
Question
A road network as shown in the figure connect four cities. In how many ways can you start from any city (say A) and come back to it without travel ling on the same road more than once ?


Options
A.8
B.12
C.9
D.16
Solution
Paths are shown as : -

Similarly if we start from A towards B we get another 4 paths.

Similarly if we start from A towards B Again 4 paths
∴ Total different paths = 4 × 3 = 12
II Method → 3C1 ×; 2C1 × 2C1 = 12

Similarly if we start from A towards B we get another 4 paths.

Similarly if we start from A towards B Again 4 paths
∴ Total different paths = 4 × 3 = 12
II Method → 3C1 ×; 2C1 × 2C1 = 12
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