Number system 11 की Divisibility related

Divisibility by 11

Tests of divisibility by 11

The number 10^N-1 is divisible by 11 for :

The number 10^(N) - 1 is divisible by 11 for :

Select the number that is related to the third number in the same way as the second number is related to the first number -13/11 : 11/13 :: 7/5: ?

Select the number that is related to the third number in the same way as the second number is related to the first number -13/11 :11/13 :: 7/5:?