So notice that at the beginning of the motion, the object moves to 16m in a span of about 10 seconds. You should know that the velocity in a pvt graph is the slope, so here the v = 1.6 m/s more or less. At 20 seconds, the object doesn't seem to be moving and you see it stays still from 10-26ish seconds. From observing you can tell that there is no velocity, but the slope of this segment is zero so you can be sure of it.
