In this type of questions, take one of the components and find its proportion in the overall mixture.
In first tank, Oil/Water = 5/8 therefore, Oil/Mixture = 5/13
In second tank, Oil/Water = 7/19 therefore, Oil/Mixture = 7/26
Therefore,
= )
= ) = 2x
= ) 2x =
= ) x =
Therefore, Oil : Mixture = = ) Oil : Water
Correct Answer: 17:35