Select the option that is related to the fourth term in the same way as the first term is related to the second term and the fifth term is related to the sixth term.

11 : 91 :: ? : 154 :: 15 : 127

18

Pattern followed here is :

First number × 9 - 8 = second number

Now, apply this pattern to given series

11 : 91

= 11 × 9 - 8

= 99 - 8

= 91 = second number

And,

15 : 127

= 15 × 9 - 8

= 135 - 8

= 127 = second number

similarly,

? : 154

= X × 9 - 8 = 154

X × 9= 162

X = 18

18 , is correct answer .