Question 218793
The big thing to notice here is that the difference
in their ages never changes
Let {{{f}}} = Father's age
Let {{{d}}} = Daughter's age
{{{d = f - 30}}} (always)
This is a ratio problem, so
{{{f/d = 4/1}}} (4 times as old)
And, rewriting:
{{{f/(f-30) = 4/1}}}
Multiply both sides by {{{f-30}}}
{{{f = 4*(f-30)}}}
{{{f = 4f - 120}}}
{{{3f = 120}}}
{{{f = 40}}}
{{{d = 10}}}
The Father will be 40 when he's 4 times as old as his Daughter
and that will be in 8 years since he's 32 now.
Notice that the fact that he was 16 times as old as his Daughter
when he was 32 was just thrown in to confuse you