Answer: 125 ft
Explanation:
Let x be the real remove between the two shows.
At that point, we are able set up the extent:
10 inches / 400 feet = 3.125 inches / x
To illuminate for x, able to cross-multiply and disentangle:
10 inches * x = 400 feet * 3.125 inches
10x = 1250
x = 125 feet