Reasoning : Logical Reasoning & Analytical Ability

Q 273 / 325

UPSC CSE Prelims 2013

Consider the following matrix:

3 370 7
2 224 6
1 730 X

What is the number at ‘X’ in the above matrix?

EXPLANATION

Correct Option (3)

The matrix follows a consistent logical pattern across its rows. The value in the rightmost column is determined by subtracting the value in the leftmost column from the sum of the digits of the number in the middle column.

  • For the first row: The middle number is 370. The sum of its digits is 3 + 7 + 0 = 10. Subtracting the leftmost number (3) results in 10 - 3 = 7, which is the value in the rightmost column.
  • For the second row: The middle number is 224. The sum of its digits is 2 + 2 + 4 = 8. Subtracting the leftmost number (2) results in 8 - 2 = 6, which is the value in the rightmost column.
  • Applying this pattern to the third row: The middle number is 730. The sum of its digits is 7 + 3 + 0 = 10. Subtracting the leftmost number (1) yields 10 - 1 = 9. Therefore, the number at 'X' is 9.

Incorrect Options:

  • Options 1 (5), 2 (8), and 4 (11) are incorrect because they do not adhere to the established logical pattern derived from the other rows of the matrix. The calculated value for 'X' based on the consistent rule is 9.