How many different 3-letter codes can be formed from 5 distinct letters if no letter is repeated and order matters?
Answer and explanation
Correct answer: B. 60
- Step 1: Order matters, so use permutations: nPr = n!/(n - r)!. Step 2. 5P3 = 60. Answer: 60. Why not the others: 10: That ignores the order. 125: That allows repeats. 15: That multiplies n by r.
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