Help with Linear Equations Problem

In a basketball game a field goal scores two points and a free throw scores one point. John scored 11pts in the game and David 19pts. David scored the same number of free throws as John but twice as many field goals. How many field goals did each score?

I can't seem to work this one out, I have been trying to work it out simultaneously but I don't get the right answer.

Can someone give me a jump start so I can finish the problem.

Greatly apprecitated

Thanks xoxo