Question 731087
The difference in their ages will always be {{{ 21 }}} years
So the mother's age is always {{{ d + 21 }}}
Let {{{ d }}} = daughter's age when her age is 1/4 that of her mother's
{{{ d = (1/4)*( d + 21 ) }}}
{{{ 4d = d + 21 }}}
{{{ 3d = 21 }}}
{{{ d = 7 }}}
The daughter will be 7 when her age is 1/4 that of her mother's
check:
Mother will be {{{ 7 + 21 = 28 }}}
and {{{ 7 = (1/4)*28 }}}
OK