A) 6
B) 8
C) 9
D) 7
Correct Answer: D
Solution :
Clearly the number of such \[n\] digit number is \[{{3}^{n}}\] as each place in the number can be filled by a non-zero digit. 2, 5, 7. So we find the least \[n\] such that \[{{3}^{n}}>900\]. Clearly \[n=7\]. So the correct answer is option D.You need to login to perform this action.
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