What is the maximum point on the graph?
Speed is the absolute value of velocity. Flip all the negative y-values to their corresponding positive positions.
What is the maximum point on the speed graph? Notice that this is NOT the same as the maximum point on the velocity graph.
The maximum is the greatest positive value. How does changing the graph to an absolute value graph change the possible maximum?
A correct velocity graph will have a maximum above the x-axis and a minimum below the x-axis, but the maximum point is further from the x-axis than the minimum point. In other words, |maximum| > |minimum|.