The figure below shows that a particle moving along an $x$ - axis undergoes three periods of acceleration. Without written computation, rank the acceleration periods according to the increases they produce in the particle’s velocity, greatest first.
I'm not sure if I'm correct with my answer, but would it go 1 and 2 tie, and then 3?
Yes, your answer is correct. The simple calculation behind it is that increase in velocity is given by $a\cdot t$, which corresponds to the area of each rectangle. By simply counting the squares inside each rectangle you obtain the solution you gave.