To answer this question, we pose the problem as follows:
It is known that there are 7 posters and between them there is 0.2 meters of separation, we also know that between the beginning of the corridor and the first poster of 0.2 meters, and between the last poster and the end of the corridor there is 0.2 meters from separation . That is, there is a total of 8 separations of 0.2 meters in the corridor.
This is the real length of the corridor occupied by the posters.
So, if we call x the length of the posters, we can write the following equation for x
Then the length of the posters is 0.4 meters