Question 555758
A key to age problems is the fact that the difference in
two peoples ages remains the same throughout their lives.
This is obvious, but often overlooked
Let {{{ x }}} = Andrew's age now
{{{ x + 4 }}} = Callie's age now
{{{ x + 3 }}} = Andrew's age in 3 yrs
{{{ x + 7 }}} = Callie's age in 3 yrs
You can have columns headed {{{x}}}, {{{ x + 4 }}}, {{{ x + 3 }}}, {{{ x + 7 }}}
and the last column is {{{ x + 3 + x + 7 = 2x + 10 }}}
Under the last column you have {{{ 52 }}} for the sum of their ages
Now find {{{x}}} with
{{{ 2x + 10 = 52 }}}
{{{ 2x = 42 }}}
{{{ x = 21 }}}
Now work your way back to the 1st 2 columns