What percent decrease in salaries would exactly cancel the 20 percent increase ?

$15\frac{1}{3}$% $14\frac{2}{3}$% $16\frac{2}{3}$% $33\frac{1}{3}$%

$16\frac{2}{3}$%

Let the salary be 100. After increase of 20%, it becomes 120. To bring it back to 100, it needs to be reduced by 20. Hence required percentage =$\frac{20}{120}×100=16\frac{2}{3}$%