A senatorial candidate had planned to visit seven cities prior to a primary election. However, he could only visit four of the cities. How many different itineraries could be considered?
- 640
-
840
- 520
- 920
The correct answer is: B
Explanation
Number of itineraries = 7P4=\(\frac{7!}{(7-4)!}\\
=\frac{7!}{3!}\\
=\frac{7 \times 6 \times 5 \times 4 \times 3!}{3!}\\
=840\)
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