UPSC CSE Prelims 2018
The rotated positions of a single solid are shown below. The various faces of the solid are marked with different symbols like dots, cross and line. Answer the three questions that follow based on the given figures.
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| (I) | (II) | (III) | (IV) |
What is the symbol on the face opposite to that containing a single dot?
EXPLANATION
Correct Option (2)
To identify the symbol on the face opposite to the single dot (·), we analyze the provided rotated positions of the solid.
By comparing Figure (I) and Figure (II):
- Figure (I) displays the faces with a single dot (·), two dots (··), and a line (-).
- Figure (II) displays the faces with two dots (··), three dots (···), and a line (-).
In these two positions, the faces showing two dots (··) and a line (-) are common. According to the principles of spatial reasoning for dice or solids, if two positions of a single solid show two common faces, then the remaining non-common faces must be opposite to each other.
Therefore, the face with a single dot (·) is opposite to the face with three dots (···).
Incorrect Options:
Options 1 (Four dots), 3 (Two dots), and 4 (Cross) are incorrect. As established by the comparison of Figure (I) and Figure (II), the face opposite to the single dot (·) is definitively the three dots (···).
