Question

What will come at the place of question mark? 7, 13, 25, 49, ?

• A. 95
• B. 97
• C. 99
• D. 101

Answer 1

Answer:

B. 97

Pattern Analysis

• The given sequence is: 7, 13, 25, 49, ?
• Observe the relationship between consecutive terms:
  • 7 to 13: (7 × 2) - 1 = 14 - 1 = 13
  • 13 to 25: (13 × 2) - 1 = 26 - 1 = 25
  • 25 to 49: (25 × 2) - 1 = 50 - 1 = 49

Calculation

• The pattern identified is: Next Number = (Current Number × 2) - 1
• Applying this logic to find the missing term:
  • (49 × 2) - 1 = 98 - 1 = 97

Alternative Method (Difference of Differences)

• Calculate the differences between consecutive terms:
  • 13 - 7 = 6
  • 25 - 13 = 12
  • 49 - 25 = 24
• The differences (6, 12, 24) form a geometric progression where each term is doubled:
  • 6 × 2 = 12
  • 12 × 2 = 24
  • 24 × 2 = 48
• Add the next difference to the last term: 49 + 48 = 97