Question 585095
{{{ ( 65 + 50 + 70 + x ) / 4 = 60 }}}
Multiply both sides by {{{ 4 }}}
{{{  65 + 50 + 70 + x  = 240 }}}
{{{ 185 + x = 240 }}}
{{{ x = 55 }}}
check answer:
{{{ ( 65 + 50 + 70 + 55 ) / 4 = 60 }}} 
{{{ 240/4 = 60 }}}
{{{ 240 = 240 }}}
OK