What is the ratio between the total number of employees in Scale III and Scale IV respectively?

Number of employees in scale III

= 75 + 250 + 320 + 120 + 85 + 100 = 950

Number of employees in scale IV

= 40 + 126 + 144 + 60 + 30 + 50 = 450

$herefore$ Required ratio = 950 : 450 = 19 : 9