Question 1

Seven books are arranged on a shelf from left to right: Fiction, Mystery, Science, History, Poetry, Art, and Biography. Science is third from the left. Mystery is immediately to the left of Science. Fiction is to the left of Mystery. History is immediately to the right of Science. Poetry is not at either end. Art is to the right of History. Biography is at the right end. Which book is second from the left?

Accepted Answer

Position 3 = Science. Position 2 = Mystery (immediately left of Science). Position 1 = Fiction (left of Mystery). Position 4 = History (immediately right of Science). Position 5 or 6 = Poetry (not at ends). Position 7 = Biography (right end). Art must be at position 5 or 6 (right of History). If Poetry at 5, Art at 6. If Poetry at 6, Art at 5. Either way, position 2 = Mystery.

Question 2

Five boxes labeled A, B, C, D, and E are stacked vertically. Box C is immediately above Box B. Box A is at the bottom. Box E is above Box D but not at the top. Box D is above Box C. Which box is at the top?

Accepted Answer

Using the constraints: A is at bottom (position 1). C is immediately above B, so they occupy consecutive positions. D is above C. E is above D but not at top. Arranging: Position 1 = A, Position 2 = B, Position 3 = C, Position 4 = D, Position 5 = E. Therefore E is at the top.

Question 3

Four colored boxes are stacked: Red, Blue, Green, and Yellow. The Red box is not at the bottom. The Blue box is immediately above the Green box. The Yellow box is at the bottom. The Green box is not at the top. In which position is the Red box?

Accepted Answer

Position 1 (bottom) = Yellow. Blue is immediately above Green, so they are consecutive. Green is not at top, so Green cannot be at position 4. Red is not at bottom. If Green at position 2, Blue at position 3, Red at position 4 (top). This satisfies all constraints.

Question 4

Five boxes labeled A, B, C, D, and E are stacked vertically in positions 1 to 5 (1 = bottom, 5 = top). The following conditions apply:
1. Box C is exactly 2 positions above Box A.
2. Box B is immediately above Box D.
3. Box E is not at the top.
4. Box A is not at the bottom.

Which box is at position 3?

Accepted Answer

This is a constraint satisfaction puzzle requiring systematic elimination. From condition 1, C is 2 above A, so possible pairs are: A at 1→C at 3, A at 2→C at 4, or A at 3→C at 5. Condition 4 eliminates A at 1. From condition 2, B is immediately above D. Condition 3 eliminates E from position 5. Testing A at 2, C at 4: B and D must be consecutive. If B at 1, D at 0 (impossible). If B at 3, D at 2 (impossible—A is there). If B at 5, D at 4 (impossible—C is there). Testing A at 3, C at 5: B and D consecutive in positions 1-2 or 1-4. If B at 2, D at 1: positions are D(1), B(2), A(3), E(4), C(5). Verify all conditions: C is 2 above A ✓, B above D ✓, E not top ✓, A not bottom ✓. Position 3 = A.

Question 5

Six colored boxes (Red, Blue, Green, Yellow, Orange, Purple) are arranged in a stack from position 1 (bottom) to 6 (top). The following clues are given:
1. Red is 3 positions below Green.
2. Yellow is immediately above Blue.
3. Purple is at an even position.
4. Orange is not adjacent to Red.
5. Yellow is not at position 6.

Which box is at position 4?

Accepted Answer

From condition 1, Red is 3 below Green: (R=1,G=4), (R=2,G=5), or (R=3,G=6). From condition 2, Yellow-Blue are consecutive. From condition 5, Yellow ∉ {6}, so Blue ∉ {6}. Testing (R=1,G=4): Remaining {2,3,5,6} for {B,Y,O,P}. Yellow-Blue consecutive in {2,3,5,6}: (B=2,Y=3), (B=5,Y=6 invalid), (B=3,Y=4 invalid). So B=2,Y=3. Then O,P in {5,6}. Condition 3: P at even → P=6, O=5. Check condition 4: Orange(5) not adjacent to Red(1) ✓. Valid: R=1,B=2,Y=3,G=4,O=5,P=6. Position 4 = Green.

Question 6

Five boxes labeled A, B, C, D, and E are stacked vertically in positions 1 (bottom) to 5 (top). The following conditions apply:
1. Box C is exactly 2 positions above Box A.
2. Box B is immediately above Box D.
3. Box E is not at the top.
4. Box A is not at the bottom.

Which box is at position 3?

Accepted Answer

This is a constraint satisfaction puzzle requiring systematic elimination. From condition 1, C is 2 positions above A, giving pairs: (A=1,C=3), (A=2,C=4), or (A=3,C=5). Condition 4 eliminates A=1. From condition 2, B and D are consecutive. Condition 3 eliminates E=5. Testing (A=2,C=4): B-D must fit in {1,3,5}. If B=1,D=2, then E=3,5 but E≠5, so E=3. If B=3,D=4, D conflicts with C. If B=5,D=4, D conflicts with C. Testing (A=3,C=5): B-D in {1,2,4}. If B=1,D=2, E=4. If B=4,D=5, D conflicts with C. If B=2,D=3, D conflicts with A. Valid: A=3,B=1,D=2,E=4,C=5. Position 3 = A.

RRB NTPC Box / Stack Puzzle

Box / Stack Puzzle— Rules & Concept

Key Points to Remember

Exam-Specific Tips

Box / Stack Puzzle — Practice Questions

60-Second Revision — Box / Stack Puzzle