Tuesday, August 28, 2018

logical deduction - Water island puzzle


On a planet called T, there exists a continent called P, which is surrounded on all sides by water. The continent comprises eight countries – A, R, B, C, D, E, G and K – located contiguously on it, i.e., the total area of the eight countries is the same as the area of the continent.


Each country is exactly in the shape of a square, with the four edges of the square as its boundaries. The areas of the eight countries are all equal. Any country is said to be a neighbour of another country if the two countries have one edge as a common boundary.


Further, one can travel by land between two countries only if the two countries are neighbours and it is known that one can reach any country from any of the other countries by travelling by land (passing through one or more countries, if required).


It is also known that




  • R and E are the only neighbours of D, while K is the only neighbour of B, but K is not to the west of B.

  • A and D are the only neighbours of E, while K is the only neighbour of C.

  • E is directly to the north of R.

  • G is directly to the east of D and no country is present directly to the south of G.


Source: time


What is the approach for this puzzle? Q:



Which of the following countries is to the immediate South of K?
a) B

b) C
c) G
d) No country is to the immediate South of K.




Answer



I have the same solution as already posted. Without following its reasoning, here is mine:



Quickly establish that E - D - R must run north to south. Now G is somewhere east of D but not adjacent


 
E

|
D G
|
R

G must be approached from the north.
Only A or K can touch G.
Only A or K can touch E.
Suppose it is E - K - A - G
 

E - K - A
| |
D G
|
R

Now B and C must touch K but one of them would have to join D and G.
But both B and C only have one neighbour K.
So it must be E - A - K - G and as K is not to the west of B it must be:
 

B
|
E - A - K - C
| |
D G
|
R

So the answer is




c) G is to the immediate South of K.



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