Analogy

What is an analogy?

An analogy is a comparison of two relationships. In daily life you may say, "a teacher works in a school just as a doctor works in a hospital". Both pairs share one link: a person and the place where that person works. In the exam this is written as Teacher : School :: Doctor : Hospital. Read the single colon ( : ) as "is to" and the double colon ( :: ) as "as".

The question shows three terms and hides the fourth, or shows one pair and asks you to pick a matching pair. You are not tested on how much you know about the words or numbers. You are tested on one skill: can you name the link correctly and copy it without changing it?

The four-step method

1. Say the link as one full sentence. "The second word is the young one of the first." "The second number is the first multiplied by 5." "Each letter moves 2 places forward."
2. Keep the direction. If the first pair goes adult → young, the second pair must also go adult → young. Cow : Calf :: Horse : Foal, not Horse : Mare.
3. Apply the same sentence to the third term. Do not invent a new rule for the second pair.
4. Test every option. If two options seem to fit, your sentence is too loose. Make it sharper (add gender, add "measures", add "made from") until only one option survives.

Kinds of analogy

Kind	Example	What decides the answer
Word	Pen : Write :: Knife : Cut	meaning or use
Letter	ACE : BDF :: GIK : HJL	alphabet positions
Number	3 : 27 :: 5 : 125	an arithmetic rule
Mixed	C5 : F10 :: H8 : K16	a letter rule and a number rule
Number set	(2, 4, 8) and (3, 9, 27)	one rule joining all three numbers

Formats of the question

• Single blank at the end: A : B :: C : ? — the most common form.
• Blank at another place: ? : B :: C : D or A : ? :: C : D. Find the rule from the complete pair and run it backwards if needed. If 5 : 125 is "cube", then ? : 64 means "which number cubed gives 64?" — the answer is 4.
• Three-term analogy: A : B : C :: D : E : ? — one rule joins all three terms in order. In 2 : 4 : 8, the terms are 2¹, 2², 2³, so 3 : 9 : ? needs 3³ = 27.
• Double blank: A : ? :: ? : D — each option gives two words or numbers. Put both into the blanks and keep the option where both halves follow the same rule.
• Pair selection: "Select the pair that is related in the same way as X : Y". Name the link of X : Y and test all four pairs.

Precision decides close options

Many options come from the same field on purpose. In Thermometer : Temperature :: Odometer : ?, the options may be Distance, Speed, Kilometre and Car. All are about vehicles, but the link is "instrument : quantity it measures". An odometer measures distance; speed is measured by a speedometer, and a kilometre is only a unit of distance. The sharper sentence removes the traps.

Common traps

• Reversing the direction (young → adult in one pair, adult → young in the other).
• Picking an option only because it is from the same topic (another animal, another number), not because it has the same link.
• Using one rule for the first pair and a slightly different rule for the second pair.
• Stopping at the first option that "looks right" without checking the other three.

Quick revision

• ":" = is to, "::" = as. The link must be copied exactly, in the same direction.
• Method: name the link in one sentence → apply → test all four options.
• Missing first term? Run the rule backwards (divide instead of multiply, subtract instead of add).
• Three-term: one rule links all three terms in order. Double blank: both halves must use the same rule.
• Two options fit? Sharpen the sentence (gender, unit vs quantity, tool vs product, part vs material).