Question

if n houses have k windows, write an expression to represent the number of windows for n + 1 houses
n+ 1 = 4+4k

Answer 1

There are on average k/n windows/house

So, n+1 houses have k + k/n windows

where'd you get the 4?

Answer 2

W = (n+1)/n * k = (kn+k)/n = k +k/n.

Answer 3

The 4 comes from each house having 4 windows according to the image above!