Question

Convert the binary number 10101 to its base 10 equivalent. 12 21 22 31

Answer 1

$\\ \sf\Rrightarrow (10101)_2$

$\\ \sf\Rrightarrow 1\times 2^0+0\times 2^1+1\times 2^2+0\times 2^3+1\times 2^4$

$\\ \sf\Rrightarrow 1+4+16$

$\\ \sf\Rrightarrow (21)_{10}$