Study the given pattern carefully and select the number from among the given options that can replace the question mark (?) in it.
| 11 | 14 | 75 |
| 15 | 16 | 31 |
| 9 | ? | 88 |
Correct Answer :
13
Solution :
The correct answer is 13.
Let's study the table carefully:
| Col 1 | Col 2 | Col 3 |
|-------|-------|-------|
| 11 | 14 | 75 |
| 15 | 16 | 31 |
| 9 | ? | 88 |
We need to find the relationship between the three numbers in each row. Let us denote the three numbers in a row as A, B, and C.
Step 1: Test Row 1 (11, 14, 75)
Notice that:
A + B = 11 + 14 = 25
B - A = 14 - 11 = 3
Now multiply: (A + B) × (B - A) = 25 × 3 = 75 ✓
This matches C = 75!
Step 2: Verify with Row 2 (15, 16, 31)
A + B = 15 + 16 = 31
B - A = 16 - 15 = 1
(A + B) × (B - A) = 31 × 1 = 31 ✓
This matches C = 31! The pattern is confirmed:
Pattern: (A + B) × (B - A) = C
This is actually the algebraic identity:
Step 3: Apply the pattern to Row 3 (9, ?, 88)
Let ? = x. Then:
Step 4: Verify
(9 + 13) × (13 - 9) = 22 × 4 = 88 ✓
The number that replaces the question mark is 13.
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