To find the length of the wall in the scale drawing, you can use the given scale: 0.5 in. : 6 feet.
This scale means that for every 0.5 inches on the drawing, it represents 6 feet in reality.
Now, you want to find the length of a 30-foot wall on the drawing:
Length on the drawing = (Actual length / Scale)
Length on the drawing = (30 feet / 6 feet) * 0.5 inches
Length on the drawing = (5) * 0.5 inches
Length on the drawing = 2.5 inches
So, the length of the wall in the drawing will be B. 2.5 inches.