Question

Directions for questions 49 to 52: There are exactly ten stores and no other buildings on a straight street in Bistupur Market. On the northern side of the street, from west to east, are stores 1, 3, 5, 7, and 9. On the southern side, also from west to east, are stores 2, 4, 6, 8, and 10. The stores on the northern side sit directly across the street from the stores on the southern side, facing each other in pairs: 1 and 2; 3 and 4; 5 and 6; 7 and 8; 9 and 10.

Each store is decorated with lights in exactly one colour: green, red, or yellow. The lighting follows these rules:
1. No store has the same light colour as a store next to it on the same side of the street.
2. No store has the same light colour as the store directly across the street from it.
3. Yellow lights decorate exactly one store on each side of the street.
4. Store 4 has red lights.
5. Store 5 has yellow lights.

Which one of the following could be an accurate list of the colours of the lights that decorate stores 2, 4, 6, 8 and 10, respectively?

• A. Green, red, green, red, green
• B. Green, red, green, yellow, red
• C. Green, red, yellow, red, green
• D. Yellow, green, red, green, red

Hint:

Work out store 3 and store 6 first since their colour is forced by both a same-side neighbour and the store facing them, then use those fixed colours to test the four lists.

Answer 1

The Correct Option is B

This puzzle gives five rules about how ten stores across a street are lit in green, red, or yellow, and asks which one of four possible colour lists for stores 2, 4, 6, 8, and 10 could actually happen. Instead of working out every store's colour first, we can test each option directly against the five rules and throw out any option that breaks one.

1. Option 1: green, red, green, red, green: this list has no yellow at all among stores 2, 4, 6, 8, 10. Rule 3 says yellow must appear on both the north side and the south side exactly once, so the south side (which is exactly this list of five stores) needs one yellow store. Since this list has zero yellow stores, it breaks rule 3 and is not possible.
2. Option 2: green, red, green, yellow, red: here store 4 is red and store 5 (given directly) is yellow, which already matches the two facts we are told outright. Store 6 is green, which fits because store 6 sits next to red store 4 and faces yellow store 5, so it can be neither of those colours and green is left over. Walking down the chain, green, red, green, yellow, red never repeats a colour between neighbours, and only one store (store 8) is yellow on this side, matching rule 3. Nothing here conflicts with any rule.
3. Option 3: green, red, yellow, red, green: this puts yellow at store 6. But store 6 faces store 5, which is yellow, and rule 2 forbids a store from sharing a colour with the store directly opposite it. So store 6 cannot be yellow, and this option is ruled out on that count alone.
4. Option 4: yellow, green, red, green, red: this puts store 4 at green, but we are told directly that store 4 is red, so this option contradicts a given fact immediately and cannot be right.

Only option 2 survives every rule check, so it is the one list of colours that could actually describe stores 2, 4, 6, 8, and 10.

Let's summarize:

• Store 4 is fixed as red and store 5 as yellow by the question itself, so any option that puts a different colour there is wrong right away.
• Store 6 is forced to green because it neighbours red (store 4) and faces yellow (store 5), leaving no other choice.
• Rule 3 forces exactly one yellow store on the south side, which rules out lists with zero or misplaced yellow stores.

So the correct list is green, red, green, yellow, red, which is option 2.