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How many 3-digit numbers are there with no digit repeated? |
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Answer» In forming a 3 digit number the 100’s place can be occupied by any 9 out of 10 digits (0 not included because it will lead to formation of 2 digit number.) The 10’s place can be occupied by any of the remaining 9 digits (here 0 can or cannot be used.) In one’s place any of the remain 8 digits can be used. So total 3-digit numbers with no digit repeated are: 9 × 9 × 8 = 648. |
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