Question 646645
Let {{{ s }}} = the number of students in the class
given:
{{{ s - (2/3)*s - (1/4)*s = 4 }}}
{{{ s*( 1 - 2/3 - 1/4 ) = 4 }}}
{{{ s*( 12/12 - 8/12 - 3/12 ) = 4 }}}
{{{ (s/12)*( 12 - 8 - 3 ) = 4 }}}
Multiply both sides by {{{ 12 }}}
{{{ s*( 12 - 11 ) = 48 }}}
{{{ s = 48 }}}
There are 48 students in the class
check:
{{{ s - (2/3)*s - (1/4)*s = 4 }}}
{{{ 48 - (2/3)*48 - (1/4)*48 = 4 }}}
{{{ 48 - 32 - 12 = 4 }}}
{{{ 48 - 44 - 4 }}}
{{{ 4 = 4 }}}
OK