Question

You decide to redecorate a wall by hanging two new posters on it. The wall is 15 feet wide and each poster is 3 feet wide. You want to place the posters on the wall so that the distance from the edge of each poster to the nearest edge of the wall is the same as the distance between the posters, as shown in the diagram below. Then the distance = feet.

Answer 1

Let the distance between be $x$.
According to the diagram,
$x+x+x+3+3=15$
$\Rightarrow 3x+6=15$
Subtracting with $6$:
$\Rightarrow 3x+6-6=15-6$
$\Rightarrow 3x=9$
Dividing both the sides by $3$,
$\Rightarrow \frac{3x}{3}=\frac{9}{3}$
$\Rightarrow x=3$ feet