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Hey Fellows,
Try this question.

Is a^2 + b^2 >= 130?

1. a/b = 3/11.
2. a < 3.

OA  E .

pm4553 · Answer

E

1) It's a ratio, so a & b can be any number. Insuff
2) Not helpful; a = -infinity to +2. Insuff

combine, you get nothing.

testprep2010 · Answer

Ans:E

1. a/b = 3/11.
when a=6, b=22 then a^2 + b^2>130
when a=.6, b=2.2 then a^2 + b^2<130
So insufficient

2. a < 3.
when a=.6, b=2.2 then a^2 + b^2<130
when a=-6, b=-22 then a^2 + b^2>130
So insufficient

gurpreetsingh · Answer

I m confused between C n E. pls letme know where I m wrong. clearly 2nd eq is not sufficient. Take 1st eq... take a=3x and b =11x put in the question.....we get 9x^2 + 121x^2 >= 130 => 130x^2 >=130 x^2>=1 , thus we need to know whether this satisfy or not. If we consider eq 2... a<3 that means x<1 Thus this should be C...but one case when x=1 we hav not consider this might take it to E. Pls advice.

Bunuel · Answer

You did everything right, except the last step:  x^2\geq{1}  -->  x\leq{-1}  or  x\geq{1}  -->  a\leq{-3}  or  a\geq{3} . So still E.

You can use number plugging when considering statements together: For  a=0.3  and  b=1.1  answer is NO, but for  a=-3  and  b=-11  answer is YES.

Hope it helps.

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