Solving for time in a frustrating dynamics question

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Homework Statement


If a car has an emergency breaking system that can be pulled by the driver, which will decelerate the car at a rate of -4.0m/s^2, how long does the driver have to react before it is too late. (If she enters the intersection at all is it too late?)

Homework Equations


No idea, but lots of information already solved in previous questions... picture below.

The Attempt at a Solution


I have literally no idea. Any help is greatly appreciated!
Handwritten physics assignment page with a kinematics problem about a car approaching an intersection, showing worked solutions with equations for time and final velocity, and variables listed in the margins.
 
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  • Handwritten physics assignment page with a kinematics problem about a car approaching an intersection, showing worked solutions with equations for time and final velocity, and variables listed in the margins.
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These sorts of problem are often more easily "grocked" using a graphical approach.

Hint: The area under a velocity versus time curve is the distance traveled.
 
Perhaps start by assuming the car stops just before entering the interaction and work back from there.
 
Have you ever hear of the SUVAT equations? One of these equations will allow you to solve this problem. Can you guess which one to use?