Correct Answer - Option 1 : 21 : 20

**Given **

Ratio of number of worker reduces = 7 : 4

**Formula Used **

Total Wages = number of worker × wages per person

**Calculation **

Total wages before reduction of workers = 7x × 3y = 21xy

Total wages after reduction of workers = 4x × 5x = 20 xy

Ratio of wages (previous : now) = 21xy : 20xy = 21 : 20

**∴ The required answer is 21 : 20 **