.
To get the answer, you should divide the sum of the lengths by the difference of the speeds
time = = 53 seconds.
Solved.
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Never saw so long buses.
Probably, you want to say "trains" instead of "buses".
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See closely related lessons
- A train passing a telegraph post and passing a bridge
- A train passing a platform
- A train passing through a tunnel
- A light-rail train passing a walking person
- A train passing another train (*)
in this site,
and especially the lesson marked (*) in the list as the most relevant to your problem.
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If you need a justification for the solution, here it is.
Use the coordinate system, connected with the slower "bus".
In this coordinate system, the slower bus is "unmoved", and the faster train moves with the speed which is
the relative speed of the buses, i.e. the difference of the speeds.
The rest is OBVIOUS.
In this problem, using this moving coordinate system is a standard method of the solution.