Four different positions of a dice are shown below. How many dots will be on the face opposite to the face which contains one dot?

Explanation:
From the first and second positions, it is found that the adjacent faces to the face containing point 1 have points 2,3 and 5. From the second position, it is also found that the face opposite to the face which contains point 1, should be adjacent to the faces containing points 2 and 5. From the third position, it is clear that the adjacent face to the faces containing points 2 and 5, contains point 6. Therefore the face opposite to the face containing point 1 must have 6 points.