Solution for this puzzle.
There are three glasses. Assume that the glass names are B1, B2, and B3.
B1 is blank, B2 is 13 liters, and B3 is 7 liters.
Now follow these steps:
Step 1: Take B2 and B3 glasses, which is (13 + 7 liters) and add into B1. Then you see B1 at 19 liters, B2 blank, and B3 at 1 liter.
Step 2: Take B3 at 1 liter and add it into B2. Then you see B1 at 19 liters, B2 at 1 liter, and B3 blank.
Step 3: Take B1 and add it into B3. Then you see B1 at 12 liters, B2 at 1 liter, and B3 at 7 liters.
Step 4: Take B3 and add it into B2. Then you see B1 at 12 liters, B2 at 8 liters, and B3 blank.
Step 5: Take B1 and add it into B3. Then you see B1 at 5 liters, B2 at 8 liters, and B3 at 7 liters.
Step 6: Take B3 and add it into B2. Then you see B1 at 5 liters, B2 at 13 liters, and B3 at 2 liters.
Step 7: Take B2 and add it into B1, and B3 add into B2. Then you see B1 at 18 liters, B2 at 2 liters, and B3 blank.
Step 8: Take B1 and add it into B3. Then you see B1 at 11 liters, B2 at 2 liters, and B3 at 7 liters.
Step 9: Take B3 and add it into B2. Then you see B1 at 11 liters, B2 at 9 liters, and B3 blank.
Step 10: Take B1 and add it into B3. Then you see B1 at 4 liters, B2 at 9 liters, and B3 at 7 liters.
Step 11: Take B3 and add it into B2. Then you see B1 at 4 liters, B2 at 13 liters, and B3 at 3 liters.
Step 12: Take B2 and add it into B1, and B3 add into B2. Then you see B1 at 10 liters, B2 at 7 liters, and B3 at 3 liters.
This is the final step: Take B3 and add it into B2. Then you will see Bottle one at 10 liters, Bottle two at 10 liters, and Bottle three blank.
I know my language is quite difficult to understand. Just try and solve.
B1 means Glass one, B2 means Glass two, and B3 means Glass three.
I hope you all understand.