Question 895981
Think of one plane as standing still and the 
other plane flying at the sum of their speeds
Let {{{ s }}} = the speed of the faster plane
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{{{ 1540 = ( s + s - 110 )*2 }}}
{{{ 1540 = 4s - 220 }}}
{{{ 4s = 1760 }}}
{{{ s = 440 }}}
{{{ s - 110 = 330 }}}
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The west bound plane flies at 440 mi/hr
The east bound plane flies at 330 mi/hr
check:
East bound train:
{{{ d[1] = 440*2 }}}
{{{ d[1] = 880 }}} mi
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West bound train:
{{{ d[2] = 330*2 }}}
{{{ d[2] = 660 }}} mi
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{{{ d[1] + d[2] = 880 + 660 }}}
{{{ d[1] + d[2] = 1540 }}} mi
OK