Six numbers, 5, 10, 15, 20, 25 and 30, are written on different faces of a dice. In two different positions of this dice, the faces adjacent to 15 are (5, 10) and (20, 25) respectively. Select the number that will be on the face opposite to the face having the number '15'.

Two positions of the same standard non-verbal dice are shown. If the numbers 1, 3, 5 are adjacent to 6 on one position and 1, 4, 5 on another, which face is opposite the face marked 6?

Two different positions of the same dice are shown, the six faces of which are numbered from 1 to 6. If faces 1, 2, 3 and 1, 5, 6 share common configurations such that 3 is adjacent to 2, and 5 is adjacent to 6, select the number that will be on the face opposite to the one showing '1'.