Question 1024328
Let the speed of the trains = {{{ s }}}
The trains are passing eachother with 
speed  = {{{ 2s }}}
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In order to cross eachother, each train 
covers {{{ 2*180 = 360 }}} m
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convert seconds to hrs:
{{{ 12*(1/60)*(1/60) = 12/3600 }}}
{{{ 12/3600 = 1/300 }}} hrs
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{{{ 360 = 2s*( 1/300 ) }}}
{{{ 360 = s*( 1/150 ) }}}
{{{ s = 54000 }}} m/hr
{{{ s = 54 }}} km/hr
The speed of each train is 54 km/hr