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

11 : 1309 :: 15 : 3345 :: 7 : ?

329

11 : 1309 :: 15 : 3345 :: 7 : ?

The logic Followed here is

Ist number × (First term² - 2) = IInd number

As

11 × (11² - 2)

= 11 × (121- 2) 

= 11 × (119)

= 1309

And

15 × (15² - 2)

= 15 × (225 - 2) 

= 15 × (223)

= 3345

Similarly

7 : ?

7 × (7² - 2)

= 7 × (49 - 2) 

= 7 × (47)

= 329