Two positions of a dice are shown below. When 3 is at the bottom, what number will be at the top?

As per the given pattern in question figure , we can find the similar next position of given dice .
Here 2 and 4 dots are at the same side .
From figure 2 and 4 are adjacent to both 3 and 6 hence 6 will be opposite to 6. '3' lies opposite '6'.

According to given dice , we can say that
Two, three, four and six dots are on the faces adjacent to one dot.
Therefore, five dots are on face opposite one dot.
One dot, three dots and five dots are on the faces adjacent to two dots.
From the second view of the cube it is clear that four dots are on the face adjacent to two dots.
Therefore, six dots are on the face opposite two dots.

On the basis of question figure pattern ,we can see that
Six faces of the dice are A, B, C, D, E and F. A is adjacent to B. E is adjacent to D and F.
Hence , E is the side opposite to A .

On the basis of following pattern in given dices , we can say that
Here the common faces with star and rhombus are in same positions .
From the given positions of a dice, it is clear that circle would be at the bottom, when the heart shape is at the top.

On the basis of following pattern in given dices , we can say that
The numbers 1, 3, 4 and 6 are on faces adjacent to number 5.
Therefore, 5 lies opposite 2.

On the basis of following pattern in given dices , we can say that
There are 2, 3, 4 and 6 dots respectively on the adjacent faces of the face having 5 dots.
Therefore, the face with one dot will be opposite the face having 5 dots.
There are 1, 3, and 5 dots respectively on the adjacent faces of the face having two dots.
Therefore, either 4 or 6 dots will be on the face opposite of the face having two dots.
Now, 4 and 6 dots cannot be on the opposite faces.
Clearly, 6 dots are there on the face opposite to the face with two dots.

On the basis of following pattern in given dices , we can say that
Here the common faces with 3 dots are in same positions .Thus , When '2' is at the bottom, number '1' will be on the top.

On the basis of question figure pattern ,
From the given views of dice it is clear that the numbers 2, 3, 4, and 5 cannot be on the face opposite 1.
Hence, 6 must be on face opposite 1.
Therefore, when 6 is on the top face 1 must be on the bottom face.

According to the rule (2) of dice , we have
There are respectively one, three, five and six dots on faces adjacent to the face having two dots.
So, four dots lies on the face opposite to the two dots.
Therefore, six dots are on the face opposite to one dot.

On the basis of question figure pattern , we have
Blue, Pink, Yellow and Green colours are on the faces adjacent to Red.
Therefore, Black colour is opposite to Red.