Question 913525
In words:
( quarts ) x ( price / quart )  = total price
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Let {{{ p }}} = price/quart of orange juice
{{{ p - 1 }}} = price/quart of grape juice
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{{{ 1.5p + 2.5*( p - 1 ) = 12.5 }}}
{{{ 1.5p + 2.5p - 2.5 = 12.5 }}}
{{{ 4p = 12.5 + 2.5 }}}
{{{ 4p = 15 }}}
{{{ p = 3.75 }}}
and
{{{ p - 1 = 2.75 }}}
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The price/quart of orange juice is $3.75
The price/quart of grape juice $2.75
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check:
{{{ 1.5p + 2.5*( p - 1 ) = 12.5 }}}
{{{ 1.5*3.75 + 2.5*2.75 = 12.5 }}}  
{{{ 5.625 + 6.875 = 12.5 }}}
{{{ 12.5 = 12.5 }}}
OK