[R] Reasoning Tricks - 2 [Cubes/Dices]

In this article I will take up CUBES/DICES. They may pose a problem to you if you are not good at imagining things in 3D. So let's begin.
Firstly you should know that there are 2 types of dice - Standard and Ordinary.
In a standard dice, the sum of opposite faces is 7 [Remember that], so if they ask which face is opposite to 2, you can say it is 7-2 = 5. But mostly the questions are from ordinary dice, where the sum is not 7.

There are various rules to solve the problems on dice -

1. If two sides of Dices are common
If two sides of cubes are common( has same numbers or symbols), then the remaining two will be opposite to each other.

2. If one side of Dices is common
If one side of given dices is common then list these sides (numbers on them) either in clock-wise or anti-clockwise. Comparing the numbers obtained from both dices will give you the opposite numbers.

3. If one side is common and it's place is same in both dices.

If one side is common in both cubes and its place is also same, then the remaining two sides of respective dices will be the opposite to each other.

Now let's move to a typical CGL question - 

In this question the face opposite to 2 is asked, so just look at each cube and list the neighbours of 2
From 1st cube :
Neighbours of 2 = 3,4                  ...(1)
From 2nd cube :
Neighbours of 2 = 1,3                  ...(2)
In the third cube '2' is not present, so we will skip this cube
From 4th cube :
Neighbours of 2 = 4,6                   ...(3)
Now merge all the three results and prepare a consolidated list of the neighbours
Neighbours of 2 = 1, 3, 4, 6
Note the number which is missing from the list. Here it is 5
So 5 is opposite to 2.

Answer : 5

Note : For each face, there are 4 neighbours and 1 opposite face. So make sure when you make the final consolidated list for a face, it has 4 neighbours [like our list contained 4 neighbours]

Next question

From the above figure, neighbours of 6 = 1,3,5
Note that there are only 3 neighbours in the list and hence we can't be sure of the face that is opposite to 6. Either it can be 2 or 4 (both are missing from the list)
When you encounter such situations, pick the face which is featured in most of the cubes. We can see that 3 is present in three of the cubes, so let's pick it.
Neighbours of 3 = 1, 4, 5, 6
From above data we can deduce that the face opposite to 3 is 2. Now since 2 is opposite to 3, it cant be opposite to 6. Hence the face opposite to 6 is 4
Answer : 4

Unfolded Cubes

Remember the following things when you get an unfolded cube

In short, no matter which figure of an unfolded cube is given in the question, the alternate faces are opposite to each other.

Now a SSC question - 

From the unfolded cube it is clear that-

Circle is opposite to Triangle
Square is opposite to Heart
Diamond(♢) is opposite to Clubs(♧)

(A) In option A we can see that triangle is shown adjacent to circle, but we know that they are opposite. Hence option A is wrong

(C) In option C, square is adjacent to heart, but they are opposite. Hence C is wrong
(D) In option D, diamond is adjacent to clubs, but they are opposite. Hence D is wrong.
Answer : (B)

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