Question

Tom has twice as many marbles as Luke. Together they have 39 marbles. How many marbles does Tom have?

Answer 1

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. 

Answer 2

Set up an equation and then solve for x. Luke has x amount and Tom has twice as many so that is 2x.

x + 2x =39
3x=39
Divide by 3
x= 13 so ...

Luke has 13 marbles and Tom has 2 times x so Tom has 2x13=26 marbles. 13+26=39