It is not possible to tell because there is no information on the densities of the liquids that two drank.
How many 4s are in 36
9 nine 9 9 9 9 9 9 9 9 9
9 9 9 9
A chessboard is not 9 by 9.
9 of them.
There are 81 squares in a 9 by 9 square.
9
9
The infinitely many numbers that leave a remainder when divided by 9. The infinitely many numbers that leave a remainder when divided by 9. The infinitely many numbers that leave a remainder when divided by 9. The infinitely many numbers that leave a remainder when divided by 9.
9
9