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  1. If S= {2, 3, 4, 5, 7, 9} , then the number of different three-digit number (with all distinct digits) less than 400 that can be formed from S is ?
    1. 20
    2. 40
    3. 80
    4. 120
Correct Option: A

The hundred place will be reserved for 3 or 2
5 digits are free to fill rest two places i,e., of tens and unit.

Number of required 3 digit number = 2 x 5C2 = 20



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