Question

In the following question, a letter-number series is given with one term missing as shown by question mark (?). Choose the missing term out of the given alternatives.
W-144, ?, S-100, Q-81, O-64}

• A. U-121
• B. U-122
• C. V-121
• D. V-128

Hint:

Check both \textbf{letter patterns} and \textbf{number patterns} separately in mixed series.

Answer 1

The Correct Option is A

Concept: This series is based on two parallel patterns: one involving decreasing alphabetical positions and the other involving decreasing perfect squares. Step 1:Analyze the letter pattern.
\[ W, \; ?, \; S, \; Q, \; O \] Convert to positions: \[ W(23), \; ?, \; S(19), \; Q(17), \; O(15) \] The pattern decreases by 2 each time: \[ 23, 21, 19, 17, 15 \] So the missing letter is: \[ U(21) \]
Step 2:Analyze the number pattern.
\[ 144, \; ?, \; 100, \; 81, \; 64 \] These are perfect squares: \[ 12^2, \; 11^2, \; 10^2, \; 9^2, \; 8^2 \] So the missing number is: \[ 11^2 = 121 \]
Step 3:Combine both results.
\[ \text{U-121} \]
Final Answer: U-121