A car moves along an x axis through a distance of 900 m

Question

Compute all parts of given problem:

Problem: A car moves along an x axis through a distance of 900 m, starting at rest (at x = 0) and ending at rest (at x = 900 m). Through the first 1/4 of that distance, its acceleration is +3.00 m/s². Through the next 3/4 of that distance, its acceleration is -1.00 m/s².

Part A: Find its travel time through the 900 m?

Part B: Find its maximum speed?

Please explain your answer. I know substitution is involved so be sure to give a detailed explanation on that as well.