Question

What is the decimal equivalent of binary number 10101

• A. 20
• B. 21
• C. 22
• D. 23

Answer 1

Answer: (B)

${\left(10101\right)}_2={\left(......\right)}_{10}$
= $1\times 2^4+0\times 2^3+1\times 2^2+0\times 2^1+1\times 2^o$
$=16+0+4+0+1=21.$