Question 1042609
Let {{{ t }}} = time in hrs spent driving at 50 mi/hr
{{{ 6 - t }}} = time spent driving 45 mi/hr
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{{{ 290 = 50*t + 45*( 6 - t ) }}}
{{{ 290 = 50t + 270 - 45t }}}
{{{ 5t = 20 }}}
{{{ t = 4 }}}
and 
{{{ 6 - t = 6 - 4 }}}
{{{ 6 - t = 2 }}}
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She drove for 4 hrs at 50 mi/hr
She drove for 2 hrs at 45 mi/hr
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check:
{{{ 290 = 50*t + 45*( 6 - t ) }}}
{{{ 290 = 50*4 + 45*2 }}}
{{{ 290 = 200 + 90 }}}
{{{ 290 = 290 }}}
OK