Q28 of 140 Page 276

How many 3-digit numbers are there with no digit repeated?


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 remaing 8 digits can be used.


So total 3-digit numbers with no digit repeated are:9 × 9 × 8=648.


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