Record travel along a straight path

[rlk626]

Homework Statement

A record of travel along a straight path is as follows:
1. Start from rest with constant acceleration of 2.20 m/s2 for 15.0 s.
2. Maintain a constant velocity for the next 1.65 min.
3. Apply a constant negative acceleration of −9.92 m/s2 for 3.33 s.
(a) What was the total displacement for the trip? m
(b) What were the average speeds for legs 1, 2, and 3 of the trip, as well as for the complete trip?
leg 1 m/s
leg 2 m/s
leg 3 m/s
complete trip m/s

Homework Equations

delta X = Vi t + 1/2 a t^2
Vf^2 = Vi^2 + 2 a (delta X)

The Attempt at a Solution

I'm sure how to tackle this, but here was my attempt.
delta X = (0)(15) + 1/2(2.20)(15^2) = 247.50
I'm kind of stuck at this point, I don't know what to do?!

 

[5carola5]

Can't you do the same for leg 3 as you did for leg 1? As they are pretty much the same, only the acceleration is now the other way around.