OG-11- DS-145

[ash_maverick]

Is 1/p >r/r^2+2 ?

1- p=r
2- r>0.

If i consider the stmt-1 then

1/r > r/r^2+2

In order to simplify it further, i can do a cross multlipication, that would result in
==> r^2 +2 >r^2

now looking at the above simplified inequality i can easily say that whether r>0 or r<0;

the above inequality will always be true..... So i chose optionn A. But the answer says C . Can somebody tells me what mistake i am doing? Is there any thing wrong in simplifying the inequality further.

Thanks in advance.

[nitya34]

You cant.. becoz you are assuming p*r = +ve

say , 1/2 > 1/3

you can say 3>2(Cross Multiplication)


now say, -1/3>-1/2
=>Minus 0.333>minus 0.5
can you cancel out Minus sign and say 2>3?(NO)

remember, Inequality Will Change Sign when you Cancel Minus on Both Sides

Is 1/p >r/r^2+2 ?

1- p=r
2- r>0.

If i consider the stmt-1 then

1/r > r/r^2+2

In order to simplify it further, i can do a cross multlipication, that would result in
==> r^2 +2 >r^2

now looking at the above simplified inequality i can easily say that whether r>0 or r<0;

the above inequality will always be true..... So i chose optionn A. But the answer says C . Can somebody tells me what mistake i am doing? Is there any thing wrong in simplifying the inequality further.

Thanks in advance.

[sreak1089]

Is 1/p >r/r^2+2 ?

If p=r, then above eqn becomes 1/r > 1/r + 2? right in which case
stmt # 1 is sufficient. Is this correct or did I miss something?

[hk]

Is 1/p >r/r^2+2 ?

If p=r, then above eqn becomes 1/r > 1/r + 2? right in which case
stmt # 1 is sufficient. Is this correct or did I miss something?

I think the question is not properly stated: it should be is 1/p>r/(r^2+2).

You cannot simply this futher without knowing the sign of R and P

1) Says p=r which does not help because, if both are positive then

1/r > r/ (r^2+2) and you can cross multiply and simplify.
But is both are negative then you need to invert the sign of inequality while cross multiplying.

2) r>0 No use as such without knowing the sign of p.

When combining both you know that both are positive hence we can cross multiply and simply. => Sufficient. Hence C!!!