The correct option is C If both statements taken together are sufficient to answer the question but neither statement alone is sufficien
From Statement I, x+y=20
From Statement II, x=y2
On putting x=y2 in Statement I, we get
Y2+y=20⇒y2+y−20=0
⇒Y2+5y−4y−20=0⇒y(y+5)−4(y+5)=0
⇒(y−4)(y+5)=0
∴y=4−5
(since, x and y are the positive integers, so we cannot take y = - 5)
Taking y = 4 and putting in Statement I,
X+4=20 ∴x=20−4=16
Now, x−y=16−4=12
Hence, x is greater than y by 12,
So, both statements are required to answer the question.