The Johnson family has three sons, Billy, Tommy, and Bobby. Billy is as old as Tommy and Bobby together. Last year, Tommy was twice as old as Bobby was. In two years, Billy will be twice as old as Tommy is now. How old is each son?

Billy is 6

Tommy is 4 and

Bobby is 2

Proof:

I thought about this through what I think would be logical so I decided to use even numbers. If Billy is as old as Tommy and Bobby together and then 2 years later he will be twice as old as Tommy is now.

Therefore (I did a bit of guess and check) I decided Tommy must be 4 and Bobby must be 2, so Billy will be 6.

Then, 2 years later, Billy will be 8 and 8 is 2 times Tommy's age now.