Here is a snippet of section D of the curious multiple-choice entrance exam into the exclusive BrainBashers puzzle club.
Q1. Which is the first question where c) is the correct answer?
a) Q3
b) Q4
c) Q1
d) Q2
Q2. Which is the first question where a) is the correct answer?
a) Q4
b) Q2
c) Q3
d) Q1
Q3. Which is the first question where d) is the correct answer?
a) Q1
b) Q2
c) Q4
d) Q3
Q4. Which is the first question where b) is the correct answer?
Reasoning
Let's look at Q1 first, and check each possible option:
If Q1's answer was a):
… we'll leave checking this for now, because …
If Q1's answer was b):
… we'll leave checking this for now, because …
If Q1's answer was c):
it would reference itself, and we'd learn nothing new, and we'd then have to check Q2.
So, let's start with Q2 first instead of Q1.
If Q2's answer was a):
an immediate contradiction, as Q4 can't be the first answer with a) as we've assumed Q2's answer is a).
If Q2's answer was b):
an immediate contradiction, as Q2 can't be the first answer with a) as we've assumed Q2's answer is b).
If Q2's answer was c):
Q3's answer would be a)
Q1's answer would be d)
confirming Q2's answer as c)
leaving Q4's only possible answer as b)
no contradiction.
If Q2's answer was d):
Q1's answer would be a) (*)
Q3's answer would be c)
Q4's answer would be d)
Q1's answer would be b)
but this contradicts the section marked (*).
Therefore, the only possible answer with no contradiction is when Q2's answer is c).
We can then follow Q2's answer, which leads to the answers to Q1 to Q3. Q4 must then reference itself.
Reasoning
These are the initial letters of the planets.
M = Mercury
V = Venus
E = Earth
M = Mars
J = Jupiter
S = Saturn
?
Puzzle 131
Can you draw a line through all of the edges in this picture?
Each side is broken into 2 or 3 edges, and there are also 7 edges inside that you have to cross. The line must be continuous, and cross each edge exactly once.
Note: this puzzle is not interactive, and cannot be clicked.
At the recent spring fayre, four keen gardeners were displaying their fine roses.
In total there were four colours and each rose colour appeared twice.
From the clues below, can you tell who had which colour roses?
Gardener Green had a yellow rose. Gardener Yellow did not have a red one. Gardener Red had a blue rose, but not a green one. Gardener Blue did not have a yellow one. One person with a red rose also had a green one. One person with a yellow rose also had a blue one. One of the persons with a green rose had no red. Neither of the persons with a yellow rose had a green one. No person had two roses of the same colour. No two persons had the same two colour roses, and their names provide no clues.
