Seven boxes, F, I, L, T, E, R and S, are kept one over the other but not…

2026

Seven boxes, F, I, L, T, E, R and S, are kept one over the other but not necessarily in the same order. Only R is kept above E. Only two boxes are kept between E and T. Only I is kept below L. F is not kept immediately above T. How many boxes are kept between S and I?

Answer: C. TwoConceptIn a vertical arrangement, translate each statement into an exact position or distance constraint. ‘Only X is above Y’ means Y has exactly one box…

  1. A.

    Four

  2. B.

    One

  3. C.

    Two

  4. D.

    Three

Attempted by 25 students.

Show answer & explanation

Correct answer: C

Concept

In a vertical arrangement, translate each statement into an exact position or distance constraint. ‘Only X is above Y’ means Y has exactly one box above it, namely X; similarly, ‘only X is below Y’ fixes Y one place above the bottom.

If exactly n boxes lie between two boxes, their position numbers differ by n + 1. After fixing the forced positions, use exclusions to place the remaining boxes.

Application

  1. Number the positions 1 to 7 from top to bottom.

  2. Only R is above E, so R is at position 1 and E is at position 2.

  3. There are two boxes between E and T, so their position numbers differ by 3. From E at position 2, the only possible position for T is 5.

  4. Only I is below L, so L is at position 6 and I is at position 7.

  5. The remaining positions 3 and 4 belong to F and S. Position 4 is immediately above T at position 5; because F is not immediately above T, F is at 3 and S is at 4.

Cross-check

Position (top to bottom)

Box

1

R

2

E

3

F

4

S

5

T

6

L

7

I

  • The complete top-to-bottom order is R, E, F, S, T, L, I.

  • This order has only R above E, two boxes between E and T, only I below L, and F not immediately above T.

Result

Between S at position 4 and I at position 7 are T at position 5 and L at position 6. Therefore, two boxes are kept between S and I.

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