Civil Service Exam Reviewer · Logical Reasoning · hard

Find the missing number: 81 : 63 :: 51 : 36 :: 23 : ?

1. 55
2. 9
3. 30
4. 25

Answer

B. 9

Solution

Rule: each number is paired with difference between the number and its reversal. Check: 81 → 63 and 51 → 36. So 23 → 9.

More Logical Reasoning questions

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