What are the x-coordinates of the bombs' explosions as measured by train B?

[Dgonzo15]

Homework Statement

I came across this problem in a worksheet and I am completely lost as to where to start; can someone help? The question is:

Two trains are heading at the same speed, relative to the Earth, in opposite directions. A bomb explodes on each train, but not at the same times. An observer on train A says that the x-coordinate of bomb A was twice that of bomb B. An observer on train B, using the same origin and orientation, says that the x-coordinate of bomb B was twice that of bomb A. However, they agree on the time coordinates: bomb A's time coordinate was twice that of bomb B's. What are the x-coordinates of the bombs' explosions as measured by train B?

Homework Equations

x=x'-vt?

The Attempt at a Solution

I have no clue where to start; this problem doesn't make sense to me and I need some help to actually start this problem.

 

[Fredrik]

Obviously, the first step is to translate the given statements into mathematical statements. This involves choosing a notation.