A bag contains red and blue marbles only. If you randomly pick two marbles from the bag without replacement, the probability of getting one red marble and one blue marble is 1/2. What can be said about the ratio of red marbles to blue marbles in the bag?
Let's reason through this problem:

1. Let "r" represent the number of red marbles and "b" represent the number of blue marbles.
2. The total number of marbles in the bag is r + b.
3. We know that if we pick two marbles without replacement, the probability of getting one red and one blue marble is 1/2.
4. There are two ways to pick one red and one blue marble: either picking a red marble first and then a blue marble or picking a blue marble first and then a red marble.
5. So, the probability of these two scenarios happening is:
   (r / (r + b)) * (b / (r + b - 1)) + (b / (r + b)) * (r / (r + b - 1))
6. This probability should equal 1/2 according to the given information:
   (r / (r + b)) * (b / (r + b - 1)) + (b / (r + b)) * (r / (r + b - 1)) = 1/2
7. We can simplify this equation by multiplying both sides by 2(r + b)(r + b - 1):
   2rb(r + b - 1) + 2br(r + b - 1) = (r + b)(r + b - 1)
8. This simplifies to:
   4rb(r + b - 1) = r^2b + rb^2 - r^2 - b^2
9. Rearranging the terms, we get:
   r^2 + b^2 = 3rb

From this equation, we cannot determine a specific ratio of red marbles to blue marbles in the bag. However, it does show that there is a relationship between the number of red and blue marbles that satisfies the given probability condition.