Choose A :- If the question can be answered by both the statement together but cannot be answered by using either statement alone.
Choose B :- If the question can be answerd using any statement alone.

Is X-Y positive?
1. Four times X is 2 more than Y
2. X-2Y is positive

Question

Choose A :- If the question can be answered by both the statement together but cannot be answered by using either statement alone.
Choose B :- If the question can be answerd using any statement alone.

Is X-Y positive? 
1. Four times X is 2 more than Y 
2. X-2Y is positive

anonymous · Answer

must be B since first statement says 
$$4x=y+2$$ 
you cannot conclude from this that 
$$x-y>0$$

anonymous · Answer

whoa big typo above sorry

anonymous · Answer

let me try again. knowing that $$4x=y+2$$ does not prove $$x-y>0$$ we can can solve $$x-(4x+2)>0$$ $$-3x-2>0$$ $$-3x>2$$ $$x<-\frac{2}{3}$$ telling us that IF $$4x=y+2$$ THEN $$x-y>0$$ only if $$x<-\frac{2}{3}$$

anonymous · Answer

I can tell you the answer of the question is 
with the help of both statement only we can conclude that X-Y positive.
I am not able to find the explaination for the same

anonymous · Answer

Neat question for mental gyrations:-)

Take the second condition and write as (x-y) -y so is it possible for x-y to be positive and the whole expression negative or 0? If x is 1 and y is 1/2, yes it is, so knowing that x-2y is not positive does not help u determine that x-y is positive.

I'm trying to find a way to explain it in English...

anonymous · Answer

i think after i fixed by typo my answer is correct.  we know that if the first statement is true, 
then x - y  is positive only if 
$$x<-\frac{2}{3}$$

anonymous · Answer

It require both statement to coclude the answer

anonymous · Answer

of course it is possible that 
$$x>-\frac{2}{3}$$ which would make 
$$x-y>0$$ a false statment

anonymous · Answer

Well if satellite is right in the first answer and I am right in the second, then u need both...

anonymous · Answer

x−(4x+2)>0

anonymous · Answer

is this correct?

anonymous · Answer

as 4x = y+2

anonymous · Answer

Can't we say statement 2 is enough to answer the question.There is no need of statement 1

anonymous · Answer

maybe.  lets check

anonymous · Answer

nope

anonymous · Answer

second statement not enough.  reason one would be to graph the region 
$$x-2y>0$$ and see that the region 
$$x-y>0$$ is not contained in it.  second and easier reason is just pick an example.  
put 
$$x=-4,y=-3$$ then 
$$x-2y=-4-2\times -3=-4+6=2>0$$ so that statement it true. 
but 
$$x-y=-4+3=-1<0$$ so first statement would be false.

anonymous · Answer

oh estudier sorry you got this already!

anonymous · Answer

The thing that the two statements together gives u is a lower numerical bound whereas separately you only have one variable in terms of the other.

anonymous · Answer

your example was right i just wasn't paying enough attention.  
so the answer is 
you need both

anonymous · Answer

The lower numerical bound prevents the construction of counterexamples.

anonymous · Answer

Good team work..!Appreciate it guys.

anonymous · Answer

Nice question...