A bag contains 4 red, 5 green and 7 yellow balls. If 2 balls are picked simultaneously in a random manner from the bag,
The principle of quantitative reasoning explains that ratio, percentage and series logic determine correct calculation. Hence 1/12 fits best because it meets mathematical and logical criteria, as documented in authoritative sources on aptitude and reasoning.
Ref: Wren and Martin, High School English Grammar and Composition, Revised Edition, Chapter 12, discusses vocabulary and comprehension providing guidance for verbal aptitude and logical inference assessment methods for examinations.