Juliana age is two times thomas age. the sum of their age is 21. what is thomas age?

Let's give Thomas' age the variable of x. Thus, the equation would look like this: x+2x=21

Next, you would combine like terms so you end up with this: 3x=21

After that, divide both sides by 3 so you have this: x=7

Therefore, Thomas is 7 years old.