In a certain code language, ‘cat dog monkey’ is coded as ‘55 66 88’; ‘camel cat donkey’ is coded as ‘66 99 33’ and ‘dog goat tiger’ is coded as ‘88 11 22’. How is ‘monkey’ coded in that language?
- (a)88
- (b)66
- (c)11
- (d)55
Answer
Why
Correct — D. Compare the statements two at a time and keep only what they share.
Rule: a word common to two statements must carry the code common to those two statements.
Statements 1 and 2 share the word cat and share the code 66, so cat = 66.
Statements 1 and 3 share the word dog and share the code 88, so dog = 88.
Statement 1 is cat dog monkey = 55 66 88. With 66 and 88 already assigned, the number left for monkey is 55 — option (d).
Why the others are wrong
- (a)88 — 88 is the code shared by statements 1 and 3, whose common word is dog. It belongs to dog, not monkey.
- (b)66 — 66 is the code shared by statements 1 and 2, whose common word is cat, so 66 is cat's number.
- (c)11 — 11 appears in statement 3 alone, dog goat tiger, which does not contain monkey. It can stand for goat or tiger and nothing else.
Concept
In word-and-number coding the three statements are not aligned word for word — the numbers are printed in their own order. What can be trusted is an intersection.
If two statements share exactly one word and exactly one number, that word carries that number. Two such intersections here pin down cat and dog, and monkey then falls out of statement 1 by elimination.
Four of the six words stay permanently ambiguous. Camel and donkey split 99 and 33 between them in some order, and goat and tiger split 11 and 22, with nothing in the data to separate either pair.
Key facts
- cat = 66 and dog = 88 are fixed by intersection, and monkey = 55 then follows from statement 1.
- Camel and donkey cannot be told apart, since statement 2 leaves 99 and 33 unassigned between them.
- cat and dog are both three-letter words with different codes, so the numbers are not built from letter counts.
Study next
Common traps
- Matching the words to the numbers in printed order, which the stem never promises
- Stopping at cat = 66 and marking it, because that is the first value the intersection yields
- Trying to assign a code to camel, donkey, goat or tiger, none of which the three statements determine
Three statements are given and one word is asked, and here the asked word is one that elimination reaches. The same three-statement construction is set on 13 Sep 2024, 09:00, Reasoning Q.15, where mountain stand tall is coded 33 66 44.
Related PYQs
No directly related past PYQ was found.