Question 40
MediumOriginal questionSix boxes, P, Q, R, S, T and U, are stacked one on top of another in a single pile. Positions are counted from the bottom: the bottom box is position 1. 'Above' or 'below' means anywhere higher or lower in the stack; 'immediately above' means resting directly on top of it. Each box is a different colour: black, white, red, green, blue or orange. The following is known:
1. Box S, which is black, is at the bottom.
2. Box Q is green, and it is immediately above the red box.
3. Exactly one box lies between box P and box Q, and P is below Q.
4. Box R is at the top, immediately above box T, which is blue.
5. The white box is immediately below box U.
Which one of the following statements about the stack of six boxes is true?
Show the answer and explanation
Correct answer: A
Explanation
Box S is at position 1 (clue 1). Box R is on top at position 6 with the blue box T at 5 (clue 4).
Q is green and has the red box directly under it (clue 2). Q cannot be at 2, because position 1 is black, so Q is at 3 or 4.
P is two places below Q (clue 3). If Q were at 3, P would be at 1, which is S. So Q is at 4 and P at 2, leaving U at 3.
The white box is directly under U, so P is white; the red box is directly under Q, so U is red. R takes the last colour, orange.
R, at the top, is orange, so that statement is the true one.
Worth noting
P is two places below Q, not immediately below: one box, U, lies between them.
- Concept
- Testing statements against a solved stack
- Typical timeTypical
- 80 s
- Your timeYours
- —
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