Home›MPPSC Prelims›Paper 2: General Aptitude Test (CSAT)›General Aptitude›Logical Reasoning and Analytical Ability›Deductive & Inductive Reasoning, Syllogisms, Series, Coding-Decoding›Find the missing number : [[?, 13, 49], [9, 17, 69], [13, 11, 59]]

Find the missing number : [[?, 13, 49], [9, 17, 69], [13, 11, 59]]

20222Mprelimsyear-2022p2
A.(A) 9
B.(B) 5Correct
C.(C) 7
D.(D) 11
Explanation & Solution

The correct answer is (B) 5.

  • Principle: In this matrix problem, we need to establish a mathematical relationship between the numbers in each row or column. Let us analyze the rows where the third column contains the resultant values formed by the first two columns.
  • Calculation: Examining Row 2: 9 × 4 + 17 × 2 = 36 + 34 = 70 (approximate to 69 or check alternative rule). Let us check another rule: Row 2: (9 + 17) × 2.5 or column-wise operations. Let us check column operations: Column 3 values are 49, 69, 59. Notice the pattern in Column 3: differences are 20 and 10. Let us test row formula First Number × 3 + Second Number × 2: For Row 2: 9 × 3 + 17 × 2 = 27 + 34 = 61 (incorrect). Let us test First Number × 4 + Second Number × 1: Row 2: 9 × 4 + 17 × 1 = 53. Let us test First Number + Second Number × 3: Row 2: 9 + 17 × 3 = 60. Let us re-examine standard matrix logic: (First Number × 2) + Second Number + constant or (First Number + Second Number) × factor. Let us check Row 2: 9 + 17 = 26, 69 - 26 = 43. Let us check row formula (First Number × 3) + Second Number + something. Actually, check Row 3: 13 + 11 = 24, 59 - 24 = 35. Let us test alternative relationship: First Number × 3 + Second Number + something. Let us check Option (B) 5 for the first row: If ? = 5, let us test rule: Row 1: 5 × 3 + 13 = 28, 49 - 28 = 21. Let us check (First Number × 2) + (Second Number × 2) + .... Let us check formula: First Number × 2 + Second Number × 3 -> Row 2: 9 × 2 + 17 × 3 = 18 + 51 = 69. Let us apply this exact verified formula (Column 1 × 2 + Column 2 × 3 = Column 3) to all rows: Row 2: 9 × 2 + 17 × 3 = 18 + 51 = 69. Row 3: 13 × 2 + 11 × 3 = 26 + 33 = 59. Row 1: ? × 2 + 13 × 3 = 49 ⇒ ? × 2 + 39 = 49 ⇒ ? × 2 = 10 ⇒ ? = 5.
  • Verification: The derived missing number is 5, which perfectly matches option (B). Other options (9, 7, 11) fail to satisfy the established row-wise linear equation (Col 1 × 2) + (Col 2 × 3) = Col 3.

हिंदी में प्रश्न एवं आदर्श उत्तर

विलुप्त संख्या ज्ञात कीजिए : [[?, 13, 49], [9, 17, 69], [13, 11, 59]]

A.(A) 9
B.(B) 5सही
C.(C) 7
D.(D) 11

सही उत्तर (B) 5 है।

  • नियम: इस आव्यूह (Matrix) पहेली में, प्रत्येक पंक्ति (Row) की संख्याओं के बीच एक निश्चित गणितीय संबंध स्थापित किया गया है। यहाँ तीसरी स्तंभ (Column) की संख्याएं पहली दो स्तंभों की संख्याओं पर आधारित हैं।
  • गणना: सूत्र का परीक्षण करने पर पाते हैं: (स्तंभ 1 × 2) + (स्तंभ 2 × 3) = स्तंभ 3। द्वितीय पंक्ति के लिए: 9 × 2 + 17 × 3 = 18 + 51 = 69 (सत्यापित)। तृतीय पंक्ति के लिए: 13 × 2 + 11 × 3 = 26 + 33 = 59 (सत्यापित)। प्रथम पंक्ति के लिए इस सूत्र को लागू करने पर: ? × 2 + 13 × 3 = 49, जिससे ? × 2 + 39 = 49, अतः ? × 2 = 10, जिससे ? = 5 प्राप्त होता है।
  • सत्यापन: विलुप्त संख्या 5 है जो विकल्प (B) के अनुरूप है। अन्य विकल्प (9, 7, 11) इस समीकरण को संतुष्ट नहीं करते हैं, अतः वे असत्य हैं।
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