Well, me and my son have been trying to solve a seemingly simple question but we just can not figure out the answer and how that answer is achieved:

Question:

Tony has one liter juice mixed with a proportion of 1:3

Robert also has one liter juice mixed with a proportion of 1:4

The two (Tony and Robert) mix their juices together in one jug.

1. What is the proportion of the mixed juice (Tony and Robert's)?

2. How much water (in deciliters) should be added so that Tony and Robert's mix again assumes the proportion of 1:4?

I hope some mathematician would be kind enough to help us on this. My son is kind of disappointed that we have not been able to figure out the answers and how to achieve them.

Regards,