In a certain code language, ‘IFF’ is coded as ‘21’ and ‘ARB’ is coded as ‘21’. How will ‘CAW’ be coded in that language?

Correct — C. Rule: add the alphabet positions of the letters, A=1 to Z=26.

IFF → 9 + 6 + 6 = 21
ARB → 1 + 18 + 2 = 21

Two different words landing on the same number is what makes the rule visible: the code ignores order, so it is a sum, not place value.

CAW → 3 + 1 + 23 = 27, option (c).

Why the others are wrong

• (a)
  25 — 25 is the total you reach if W is read as 21. W is the 23rd letter, and 3 + 1 + 23 = 27.
• (b)
  23 — 23 is W's own position. Adding C and A must push the total past it, so 23 cannot be the code for a word containing W.
• (d)
  26 — 26 falls one short, which is what you get from treating A as 0 instead of 1.

The first move on any number-coding item is to write each letter's alphabet position under it. Then test sum, then product, then difference.

Here the product fails at once: 9 × 6 × 6 = 324 and 1 × 18 × 2 = 36, nowhere near each other. The sum gives 21 for both.

Nothing in this item depends on where a letter sits in the word, so once the sum works there is no second rule to look for.

Key facts

• A=1, B=2 through to Z=26 is the position scale these codes use.
• I + F + F = 9 + 6 + 6 = 21.
• A + R + B = 1 + 18 + 2 = 21.
• C + A + W = 3 + 1 + 23 = 27.

Common traps

• Mis-numbering the back half of the alphabet, especially V=22 and W=23
• Trying a product because the two given codes are equal
• Assuming the code depends on the order of the letters

No directly related past PYQ was found.