Hi all
I've just practiced the GMAT CAT Veritas prep and here's my wondering question:
Is x^2 + y^2>100?
1. 2xy<100
2. (x+y)^2>200.
My answer is B because:we have x^2+y^2>=2xy with all x,y. Thus, adding x^2+y^2 to both sides of this equation we have 2(x^2+y^2)>=x^2+y^2+2xy = (x+y)^2. According to subject, (x+y)^2>200. Thus, we have reference x^2+y^2>100.
However, correct answer is C. Anyone can help me to explain?[/list][/quote]
I've just practiced the GMAT CAT Veritas prep and here's my wondering question:
Is x^2 + y^2>100?
1. 2xy<100
2. (x+y)^2>200.
My answer is B because:we have x^2+y^2>=2xy with all x,y. Thus, adding x^2+y^2 to both sides of this equation we have 2(x^2+y^2)>=x^2+y^2+2xy = (x+y)^2. According to subject, (x+y)^2>200. Thus, we have reference x^2+y^2>100.
However, correct answer is C. Anyone can help me to explain?[/list][/quote]
