Greetings from Brasil...
Observing the line of the problem we can see that each division represents -1/3. From zero to - 1 we have 3 divisions, then - 1/3 for each division.
From scratch, P is the fifth division, so
P = (- 1/3) x 5
P = - 5/3
or
P = - 1.6666...
just looking at the figure already conclude that P < - 1 and P > - 2
so P
or just P < - 1