Question 583269
She read 1/4 of her book on Monday
Tuesday she read the rest, or 3/4 of the book
Let {{{ p }}} = number of pages she read on Monday
{{{ 80 + p }}} = number of pages she read on Tuesday
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 {{{ p + 80 + p = 80 + 2p }}} = number of pages in book
{{{ (3/4)*( 80 + 2p ) = 80 + p }}}
{{{ 3*( 80 + 2p ) = 4*( 80 + p ) }}}
{{{ 240 + 6p = 320 + 4p }}}
{{{ 2p = 80 }}}
{{{ p = 40 }}}
{{{  80 + 2p = 80 + 2*40 }}}
{{{ 80 + 2*40 = 160 }}}
There are 160 pages in the book