Question 1130507
Let {{{ x }}} = the number of friends she has
{{{ 3x + 31 = 4x + 9 }}}
{{{ x = 22 }}}
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{{{ 3x + 31 = 3*22 + 31 }}}
{{{ 3x + 31 = 97 }}}
and, also
{{{ 4x + 9 = 4*22 + 9 }}}
{{{ 4x + 9 = 97 }}}
She has 97 sheets of paper