we need to make some assumptions
we don't know a few things:
1. the width of the wall
2. the width of the posters
3. the width of the gap, that we will solve for
alright, so
the width of the wall will be r
the width of each poster will be p
the width of the gap between each is w
so
make an equation for the width of the wall
3 feet on the ends (2 of them) plus the 3 posters plus the 2 gaps between each poster
that means
r=3*2+3*p+2*w
r=6+3p+2w
solving for the width
minus (6+3p) from both sides
r-6-3p=2w
divide both sides by 2
[tex]\frac{r-6-3p}{2}=w[/tex]
[tex]w=\frac{r-6-3p}{2}[/tex]
where w is the width of the gap, r is the width from wall to wall, and p is the width of each poster
