A salesman must visit 4 cities and return to the starting point. If the distances between cities are all unique, what is the minimum number of routes he needs to consider?
Category: Brain · Difficulty: hard
Hint: Consider the concept of permutations.
Answer
6
Explanation
The number of unique routes for visiting n cities and returning is (n-1)!, so for 4 cities, it's 3! = 6.
This is a hard brain riddle — a tricky one that takes a little thought. The answer is 6.
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