In a certain code language, ‘sit on chair’ is coded as 'sk mi cn' and ‘the chair broke’ is coded as ‘gm fr mi’. How is ‘chair’ coded in the given language?

Correct — C.

Rule: a word shared by two sentences must be coded by the symbol shared by their two code strings.

sit on chair = sk mi cn
the chair broke = gm fr mi

The word appearing in both sentences is chair. The symbol appearing in both strings is mi.

So chair is coded mi, which is option (c). Note that the codes are not printed in the order of the words, so position proves nothing.

Why the others are wrong

• (a)
  gm — gm appears in the second string alone, so it must stand for 'the' or for 'broke' — words that never occur in the first sentence.
• (b)
  sk — sk appears in the first string alone. It codes either 'sit' or 'on', and neither of those words turns up in the second sentence.
• (d)
  cn — cn is also confined to the first string, so like sk it codes 'sit' or 'on'. Nothing in the two sentences can attach it to chair.

Substitution codes of this kind are solved by intersection, never by matching positions.

The symbols are deliberately jumbled, so 'sit' is not necessarily 'sk'. What survives the jumbling is membership: a word in two sentences must be coded by a symbol in both strings.

Here the sentences share one word and the strings share one symbol, so the pairing is forced without any further work.

Notice what stays unknown. Nothing tells you whether sk is 'sit' or 'on', and the question does not need it to — it asks about the intersection alone.

Key facts

• The code symbols are not given in the order of the words, so position carries no information.
• chair is the word common to both sentences and mi is the symbol common to both code strings.
• sk and cn code sit and on in some order that these two sentences cannot decide.

Common traps

• Pairing the first symbol with the first word when the stem never promises that order.
• Trying to fix sk and cn as well, which these two sentences do not determine.

No directly related past PYQ was found.