Question 1

Five boxes labeled A, B, C, D, and E are stacked vertically from bottom to top. The following conditions must be satisfied:
1. Box C is not at the bottom.
2. Box A is exactly 2 positions above Box B.
3. Box D is immediately above Box E.
4. Box C is above Box A.

Which box is at the top (5th position)?

Accepted Answer

This is a linear ordering puzzle requiring systematic constraint satisfaction. Students must track multiple positional relationships simultaneously and eliminate impossible arrangements.

Question 2

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:
(i) Box C is exactly 2 positions above Box A.
(ii) Box B is immediately above Box D.
(iii) Box E is not at the top.
(iv) 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 (i), C is 2 above A, giving pairs: (A=1,C=3), (A=2,C=4), or (A=3,C=5). Condition (iv) eliminates A=1. If A=2, C=4: B and D are consecutive (condition ii), and E ≠ 5 (condition iii). Testing A=2, C=4: positions 1,3,5 remain for B,D,E. Since B is immediately above D, they must occupy (1,2)—impossible as A=2—or (3,4)—impossible as C=4—or (5,1)—impossible. So A=3, C=5: positions 1,2,4 for B,D,E. B immediately above D means (B=2,D=1) or (B=4,D=3)—impossible as A=3. Thus B=2, D=1, E=4. Position 3 = A.

Question 3

Six books—Fiction (F), History (H), Mystery (M), Novel (N), Poetry (P), and Science (S)—are arranged on a shelf in positions 1 to 6 (left to right). The following conditions hold:
(i) Mystery is 3 positions to the right of History.
(ii) Poetry is immediately to the left of Science.
(iii) Novel is not in position 1.
(iv) Fiction is to the left of Mystery.

If History is in position 2, which book is in position 5?

Accepted Answer

Given H=2, condition (i) gives M=5. Condition (iv) requires F < M, so F ∈ {1,2,3,4}. Since H=2, F ∈ {1,3,4}. Condition (ii): P is immediately left of S, so (P,S) occupy consecutive positions from {1,3,4,6}. Possible pairs: (1,2)—impossible, H=2; (3,4); (4,5)—impossible, M=5; (6,7)—impossible. Thus (P,S)=(3,4). Remaining: F and N for positions 1 and 6. Condition (iii): N≠1, so N=6, F=1. Final: F=1, H=2, P=3, S=4, M=5, N=6. Position 5 = M.

Question 4

Nine books are stacked in positions 1 to 9 (bottom to top). The books are labeled P, Q, R, S, T, U, V, W, X. The following conditions must be satisfied:
(i) Book R is exactly 4 positions above Book P.
(ii) Book S is immediately above Book T.
(iii) Book U is above Book W.
(iv) Book Q is not in position 1.
(v) Book V is in position 5.

If Book P is in position 2, which book is in position 6?

Accepted Answer

Given P=2 and V=5, condition (i) gives R=6. Condition (ii): (S,T) consecutive. Remaining positions {1,3,4,7,8,9} for {Q,S,T,U,W,X}. (S,T) consecutive from {1,3,4,7,8,9}: (3,4), (7,8), (8,9). Condition (iv): Q≠1. So Q∈{3,4,7,8,9}. Condition (iii): U > W in position. Test (S,T)=(3,4): {1,7,8,9} for {Q,U,W,X}. Q∈{7,8,9}. U>W: pairs from {1,7,8,9} where U>W. If Q=7: {1,8,9} for {U,W,X}. U>W: (U=8,W=1), (U=9,W=1), (U=9,W=8). Try U=9, W=1, X=8. Check all: P=2, Q=7, R=6, S=3, T=4, U=9, V=5, W=1, X=8. Position 6 = R.

SSC CPO 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