Question 732669
That will happen in {{{x}}} years. Let's find {{{x}}}.
In {{{x}}} years Jodie will be {{{28+x}}} years old.
At that time Dave will be {{{10+x}}} years old.
Jodie will be be twice as old as Dave, so
{{{28+x=2*(10+x)}}} --> {{{28+x=20+2x}}} --> {{{28+x-x-20=20+2x-x-20}}} --> {{{28-20=2x-x}}} --> {{{8=x}}}
So in {{{highlight(8)}}} years Jodie will be twice as old as Dave.
 
Verification:
In 8 years Dave will be {{{10+8=18}}} years old and Jodie will be {{{28+8=36}}} years old, which is twice as old as {{{18}}} years old.