[raaaid]

check your maths sir:

a plane takes two gunsights at 50 m

one gunsight at 100

0.5 gunsights at 200 m

but

at 150 m will take 3 times less than at 50 m an 1.5 times less than at 100

and efectively 2/3 = 1/1.5 = 1.666...

oh dejavu all over