How many 5-digit PIN codes can be formed using digits 0-9 if no digit may be repeated?
Answer and explanation
Correct answer: A. 30240
- Step 1: There are 10 choices for the first digit, 9 for the second, 8 for the third, 7 for the fourth, and 6 for the fifth. Step 2. Compute permutations: P(10, 5) = 10 9 8 7 6. Step 3. Multiply: 90 56 6 = 5040 6 = 30240. Answer: 30240. Why not the others:* 100000 allows repetition (10^5); 50400 multiplies by 10 instead of 6; 15120 divides by 2.
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