Question 924678
Let {{{ c }}} = number of children
{{{ 78 - c }}} = number of adults
{{{ 4 / 2 = 2 / 1 }}}
{{{ 2 / 1 = (( 78 - c )) / c }}}
Multiply both sides by {{{ c }}}
{{{ 2c = 78 - c }}}
{{{ 3c = 78 }}}
{{{ c = 26 }}}
{{{ 78 - c = 52 }}}
There are 26 children