Question 660993
Let {{{ s }}} = his speed in still air in in/min
{{{ s + 2 }}} = his speed in inches/min going with the wind
{{{ s - 2 }}} = his speed in inches/min going against the wind
Let {{{ d }}} = distance he has to travel
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given:
{{{ s + 2 = d / .8 }}}
{{{ s - 2 = d / 1.2 }}}
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{{{ d = .8*( s + 2 ) }}}
{{{ d = 1.2*( s - 2 ) }}}
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{{{ .8*( s + 2 ) = 1.2*( s - 2 ) }}}
{{{ .8s + 1.6 = 1.2s - 2.4 }}}
{{{ .4s = 4 }}}
{{{ s = 10 }}}
He travels 10 in/min in still air
check:
{{{ s + 2 = d / .8 }}}
{{{ 12 = d/.8 }}}
{{{ d = .8*12 }}}
{{{ d = 9.6 }}} 
and
{{{ s - 2 = d / 1.2 }}}
{{{ 8 = d / 1.2 }}}
{{{ d = 1.2*8 }}}
{{{ d = 9.6 }}}
OK