Question 921188
Think of this as one train standing still and 
the other traveling at the sum of their speeds
Let {{{ t }}} = time in hrs for them to meet
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{{{ 448 = ( 70 + 90 )*t }}}
{{{ t = 448/160 }}}
{{{ t = 2.8 }}} hrs
{{{ .8*60 = 48 }}}
In 2 hrs and 48 min they will meet
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check:
For slower train:
{{{ d[1] = 70*2.8 }}}
{{{ df[1] = 196 }}}
For faster train:
{{{ d[2] = 90*2.8 }}}
{{{ d[2] = 252 }}}
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{{{ d[1] + d[2] = 196 + 252 }}}
{{{ d[1] +d[2] = 448 }}}
OK