<span>they built 2.22 km per day I think</span>
The number 8 is a multiple of 16, 2 x 8 = 16 . And the number 8 + 10 = 18
So, I would think it's 8.
Hope I was able to help you. :-)
The answer for this answer would be A
Radius I think is 4
Because 8/2=4 and the diameter is 2 times the radius
Check work:
4*2=8
Have a awesome night/day