Total Bits = 8
case 1 : Starts with 0, then it must be less than 182
So, in the remaining 7 Bits, you need to choose 4 bits as 1 ==> $\binom{7}{4}$ = 35
case 2 : Starts with 1, then next bit should be 0 for total decimal value ≤ 182.
So, in the remaining 6 Bits, you need to choose 3 bits as 1 ==> $\binom{6}{3}$ = 20
but in this 20 patterns, $1011\color{red}{1}000$ is grater than given number. SO only 19 patterns are matching with our condition.
Total = 35+19 = 54