Question 30284
Lin is 10 years old so her dad is 30 years old.
Let x be the age in the futre.
Lin's age = 10+x
Her dad's age = x+30


Equation:
<pre><b>
2(x+10)=x+30
2x+20=x+30
x=10


<font color = orange>Hence, after 10 years.</font>
Paul.