#### Answer

$6$

#### Work Step by Step

The number of ways in which a series of successive things can occur is found by multiplying the number of ways in which each thing can occur.
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1. The first leg (SF-NY) travel option can be chosen in 3 ways.
2. The second leg (NY-Paris) travel option can be chosen in 2 ways.
Applying the Principle,
the total number of choices is $3\times 2=6$