Tom has twice as many marbles as luke. together they have 39 marbles. how many marbles does tom have?

Tom has 26 marbles. To get this answer, you would have to set up an equation, my equation was 2x(Tom's marbles) plus x (Luke's marbles) which is  2x+x=39. I added like terms to get 3x=39. Then I divided 39 by 3 to isolate x and got 13. Because Tom has twice as many marbles, I multiplied 13 by 2 to get Tom's marbles. 

22.