Logic Puzzles: Ordering

Methods in this video

Tap a time to jump to where the video teaches that method.

1. 1

   Put the comparisons on one vertical line

   ▶ 0:54

   When to use it: The question compares several people (or things): who is in front of whom, who is taller or faster, and asks what place someone came or who is in a certain place.

   • Put every comparison on one vertical line: in front (taller, faster) at the top, behind (shorter, slower) at the bottom.
   • If two people aren't connected yet, keep them as a short piece on the side until a later clue joins the whole piece on.
   • Draw it, then read off the places. Don't try to memorise it.
2. 2

   Turn "no one" and "only one" into places

   ▶ 1:36

   When to use it: The comparison clues use counting words such as "no one arrived after him" or "only one person was faster than him", and the question asks what place someone came.

   • Turn words like "no one" and "only one" into exact places first.
   • "No one arrived after him" means he came last; "only one person was faster than him" means he came second.
   • Read the direction carefully: who goes above, and who goes below?
3. 3

   One box per person: place the fixed ones first

   ▶ 2:49

   When to use it: People sit in a row (or things stand in a line or stack in layers), a clue fixes a place outright ("on one end", "in the middle", "third from the left"), often together with "immediately to the left / right of", and the question asks who is in a certain position.

   • Draw one box per person and mark the box the question asks about (the middle of five boxes is box 3).
   • Place the fixed people first: at one end, in the middle, or at a numbered place such as third from the left.
   • People who sit right next to each other form a chain. Put the whole chain into the empty boxes and keep its order.
4. 4

   Must not touch: most restricted first, then check every rule

   ▶ 4:08

   When to use it: Things go in a row or a stack, most rules say "must not touch" or "not next to", and no clue tells you directly where anyone goes.

   • Find the most restricted item: it can't touch the most things and has only one possible neighbour.
   • A middle place has two neighbours, so the most restricted item must go at an end.
   • When you finish, check every rule. "Directly on top of" means touching, not at the very top.
5. 5

   Unsure? Draw every case. "Must be true" means true in every drawing

   ▶ 5:29

   When to use it: All the clues are used but two things still have no fixed order, and the question asks which statement must be true.

   • If you're still unsure after using every clue, draw each possible case.
   • "Must be true" means true in every drawing. If several options work in one drawing, there is another order you haven't drawn.
   • Find only what the question asks for. You don't need to settle the parts it doesn't ask about.