If log_4 x = 12, then log_2 (x / 4) = ?

Explanation

B) 22. From log_4 x = 12, x = $4^{12}$ = $2^{24}$. Then x/4 = $2^{24}$ ÷ $2^2$ = $2^{22}$, so log_2 (x/4) = 22. A quicker route: log_2 x is twice log_4 x, so it is 24, and dividing by 4 takes away log_2 4 = 2.