By what percent the new price of the article must be increased to restore its former value, if the cost of the article is cut by 25% in the past?

$33\frac{1}{3}$%

If the cost price is cut by 25% then,

      CP           After cutting

     100             75

To restore earlier CP the CP must be increased by

    75               100

so increase percentage = ( 100 - 25 ) × \(\frac{100}{75}\) = $33\frac{1}{3}$%