Question 898420
Wilma had {{{ 40 - 10 = 30 }}} actual
hours of driving time
Let {{{ t }}} = time in hrs for her to
drive from A to B
{{{ 30 - t }}} = time in hrs for her to
drive from B to A
Let {{{ d }}} = one-way distance from A to B
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Equation for A to B:
{{{ d = 40t }}}
Equation for B to A
{{{ d = 35*( 30 - t ) }}}
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By substitution:
{{{ 40t = 35*( 30 - t ) }}}
{{{ 40t = 1050 - 35t }}}
{{{ 75t = 1050 }}}
{{{ t = 14 }}}
and
{{{ 30 - t = 16 }}}
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{{{ d = 40t }}}
{{{ d = 40*14 }}}
{{{ d = 560 }}} 
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City A is 560 miles from City B
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check:
{{{ d = 35*( 30 - t ) }}}
{{{ 560 = 35*( 30 - 14 ) }}}
{{{ 560 = 35*16 }}}
{{{ 560 = 560 }}}
OK