Find the constant acceleration of the train

[Quang]

Homework Statement

Liz rushes down onto a subway platform to find her train
already departing. She stops and watches the cars go by.
Each car is 8.60 m long. The first moves past her in 1.50 s
and the second in 1.10 s. Find the constant acceleration of
the train.

Homework Equations

The Attempt at a Solution

vi = 8.6/1.5
vf = 8.6/1.1
a = 2(vf - vi)/2.6
?
any advice? I'm confused

 

[Doc Al]

You're given distance and time, so what kinematic formula relates those two for constant acceleration?