Question 997630
Let {{{ x }}} = the monthly rent
--------------------------
{{{ x/3 - 75 = x/4 }}}
----------------------
In words:
[ each of the 3 students share minus $75 each ] = [ each students share if there are 4 ]
----------------------
Multiply both sides by {{{ 12 }}}
{{{ 4x - 900 = 3x }}}
{{{ x = 900 }}}
---------------------
The rent is $900/month
---------------------
check:
{{{ x/3 - 75 = x/4 }}}
{{{ 900/3 - 75 = 900/4 }}}  
{{{ 300 - 75 = 225 }}}
{{{ 225 = 225 }}}
OK