Re: If r<0 and 0<pq/r<1
[#permalink]
15 Apr 2023, 02:21
Given that ๐ < 0 and 0 <๐๐/๐< 1
Considering 0 <๐๐/๐, since ๐ < 0 ๐๐ ๐๐๐ฃ๐๐, thus 0 <๐๐/๐ will be true only when ๐๐ < 0
Therefore, ๐๐ is negative. โ ๐ ๐๐๐ ๐ will have opposite signs. Which implies:
i) If ๐ > 0 then ๐ < 0
OR
ii) If ๐ < 0 then ๐ > 0
Now, considering ๐๐/๐ < 1, since ๐ < 0 and when we multiply by negative value on both the sides of the inequality, the inequality signs reverses due to the reversal of the magnitude.
Hence, in ๐๐/๐< 1 multiplying with ๐ on both the sides we get, ๐๐ > r
Hence, we can definitely say that,
๐๐ < ๐ and ๐๐ > r
(A)๐ < 0
This is not always true.
We know, ๐๐ < 0, which implies that ๐ will only be negative if ๐ is positive and
nothing is given about the sign of ๐, so ๐ < 0, is not always true.
(B)๐ < 0
This is not always true.
We know, ๐๐ < 0, which implies that ๐ will only be negative if ๐ will be positive
and nothing is given about the sign of ๐, so ๐ < 0, is not always true.
(C) ๐ > ๐
This is not always true.
We know, ๐๐ < 0, which implies both ๐ and ๐ are of opposite signs. So, ๐ > ๐ will
only be true, when ๐ is positive, and ๐ is negative which cannot be definitely
concluded.
(D)๐ < ๐
This is not always true.
We know, ๐๐ < 0, which implies both ๐ and ๐ are of opposite signs. So, ๐ < ๐ will
only be true, when ๐ is negative and ๐ is positive which cannot be definitely
concluded.
(E) ๐๐ > 0
As we know, ๐๐ < 0,
So, ๐๐ > 0 can never be true.
(F) ๐๐ < 0
We have already concluded that ๐๐ < 0.
So, this option will always be true.
(G) ๐๐ < ๐
As ๐๐ < 0 and r < 0
๐๐/๐ < 1
โ ๐๐ > ๐
So, we can say that ๐๐ < ๐ cannot be true.
(H) ๐๐ > ๐
As ๐๐ < 0 and r < 0 ,
๐๐/๐< 1
โ ๐๐ > ๐
So, we can say that ๐๐ > ๐ is always true.