For every 5 feet, the scale drawing is 1 unit. So we divide the dimensions by 5 to get the dimensions of the scale drawing.
120/5 = 24
1:5 = x:120 There are 24 5's in 120 so the new ratio is 24:120
75/5 = 15
1:5 = x:75 There are 15 5's in 75 so the new ratio is 15:75
The dimensions of the scale drawing is 24 units by 15 units.