Question 1154720
Let {{{ d }}} = distance/wk driven with hybrid
{{{ 500 - d }}} = distance driven with truck
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{{{ d / 40 + ( 500 - d ) / 17 <= 20 }}} answer
solve:
Multiply both sides by {{{ 40*17 }}}
{{{ 17d + 40*( 500 - d ) <= 40*17*20 }}}
{{{ 17d + 20000 - 40d <= 13600 }}}
{{{ 23d >= 6400 }}}
{{{ d >= 278.26 }}}
and
{{{ 500 - d <= 221.74 }}}
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check:
{{{ d / 40 + ( 500 - d ) / 17 <= 20 }}}
{{{ 278.26 / 40 + 221.74/ 17 <= 20 }}}
{{{ 6.96 + 13.04 <= 20 }}}
{{{ 20 <= 20 }}}
OK