RRB NTPC · Question 43
Select the number from among the given options that can replace the question mark (?) in the following table.
| 5 | 4 | 3 |
|---|---|---|
| 6 | 5 | 4 |
| 7 | 6 | 5 |
| 384 | 245 | ? |
Show answer & explanation
Answer: (C) 144
Explanation
In each column the bottom number = middle number × (bottom number + 1)²: 6 × 8² = 384 and 5 × 7² = 245. For the third column: 4 × 6² = 144.