Question 772463
Let {{{ b }}} = the book value
She bought the lamp for {{{ .9b }}}
She sold the lamp for {{{ b + .25b = 1.25b }}}
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The profit is:
( selling price ) - ( purchase price )
{{{ 105 = 1.25b - .9b }}}
{{{ b*( 1.25 - .9 ) = 105 }}}
{{{ b = 105 / .35 }}}
{{{ b = 300 }}}
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The neighbor paid {{{ 1.25b }}}
{{{ 1.25b = 1.25*300 }}}
{{{ 1.25b = 375 }}}
$375