Let's work this out.
- Even numbers doesn't seem to be the solution. Let's say Beth had 2 dollars and Ruth had 4 dollars. That seems to be the solution because of Ruth gave a dollar to Beth, they would both have 3 dollars. However, if Beth gave a dollar to Ruth, Ruth would have 5 and Beth 1. 5 is not double of 1. This seems to be the case with every other even solution.
- Now, if Beth had 5 dollars and Ruth had 7 dollars, we can see a factual solution. If Beth gave Ruth 1 dollar, Ruth would have 8 and Beth 4. 8 is double of 4. So that works. ✓
- Then, if Ruth gave a dollar to Beth, they would both have 6 dollars. This works as well. ✓
Answer: Beth has 5 dollars and Ruth has 7 dollars.
