Delhi Police Constable Exam Model Paper 3

Concept:/Formula:
Divisibility law of 11: If the difference of the alternating sum of digits of the number is a multiple of 11 (e.g. 2343 is divisible by 11 because 2 - 3 + 4 - 3 = 0,which is a multiple of 11).
Calculation:
If the number 6X6 is divisible by 11, then
⇒ $6\mathit{–}\mathit{X}+6=11$
⇒ $12\mathit{–}\mathit{X}=11$
⇒ $\mathit{X}=12\mathit{–}11$
⇒ $\mathit{X}=1$
$\therefore \mathit{X}=1$