Consider the following pattern of numbers:
8 10 15 13
6 5 7 4
4 6 8 8
6 11 16 ?
What is the number at (?) in the above pattern?

Correct Option (1)

The given number pattern follows a specific arithmetic rule applied column-wise. For each column, the element in the fourth row is determined by the elements in the first, second, and third rows.

The established rule is: (First Row Element) + (Third Row Element) - (Second Row Element) = (Fourth Row Element).

Applying this rule to the existing columns:

• Column 1: 8 + 4 - 6 = 6
• Column 2: 10 + 6 - 5 = 11
• Column 3: 15 + 8 - 7 = 16

Applying the same rule to the fourth column to determine the missing number (?):

• Column 4: 13 + 8 - 4 = 17

Therefore, the number at (?) is 17.

Incorrect Options:

Options 2 (19), 3 (21), and 4 (23) are incorrect. These values do not conform to the established column-wise arithmetic pattern, which consistently applies the operation: (First Row Element) + (Third Row Element) - (Second Row Element) = (Fourth Row Element).