$n$ - digit numbers are formed using only three digits 2,5 and 7 . The smallest value of $n$ for which 900 such distinct numbers can be formed, is

Question

Aicharya · Accepted Answer

Required $n$ digit numbers is $3^n$ as each place can be filled by $2,5,7$. So smallest value of $n$ such that $3^n>900$. Therefore $n=7$.

$n$ - digit numbers are formed using only three digits 2,5 and 7 . The smallest value of $n$ for which 900…