Question 1000009
D=daughter's age; M=man's age=5D
X=number of years until daughter is 1/4 Father's age
.
{{{D+X=(1/4)(M+X)}}}
{{{D+X=(1/4)(5D+X)}}}
{{{4(D+X)=5D+X}}}
{{{4D+4X=5D+X}}}
{{{3X=D}}}
{{{X=D/3}}}
.
When we calculate the father's age (52-7=45) is 45,
we know the daughter is currently (45/5=9) 9 years old.
So X=D/3=9/3=3 and the daughter will be 1/4 as old in 3 years:
.
CHECK:
{{{D+X=(1/4)(M+X)}}}
{{{9+3=(1/4)(45+3)}}}
{{{12=(1/4)(48)}}}
{{{12=12}}}