Due to reduction in workforce, the production in a factory decreases by 30%. By what percentage should the working hours per person be increased to restore the original production? (Correct to two decimal places.)

42.86%

30% =  \(\frac{3}{10}\)

Ratio of  ,             Initial    :     New

Production              10       :      7

Working hours         7        :     10

{ Total production = Price × Working hours }

So Increased percentage of working hours = \(\frac{10-7}{7}\) × 100

= \(\frac{3}{7}\) × 100 

= 42.86% (approx.)