How many sons does W have?
Statements : I. X's father has three children.
II. Y is X's brother and son of W.
Read the question & statements (I & II). Decide whether the data provided in the statements are sufficient to answer the question.
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → If I & II together are not sufficient
To count W’s sons we need to know how many children W has and the gender of each. Test each statement alone and then the two together.
I alone: X’s father has three children. It says nothing about W, so it is not sufficient.
II alone: Y is a son of W and X’s brother, so X is also W’s child. W has at least one son, Y, but X’s gender and any other children are unknown, so it is not sufficient.
I and II together: if W is X’s father, W has three children: Y (a son), X and one more. The genders of X and the third child are still unknown (and W may be X’s mother), so W could have one, two or three sons.
Even together the statements cannot fix the number of sons.