Question : Is mn<0?M7MBA wrote:Is mn < 0? $$(1)\ \ \ m^5n^2<0$$ $$(2)\ \ \ m^{11}p^8n^5<0$$ The OA is the option B.
How can I know the sign of mn without knowing them? Experts, I would appreciate your help here.
Statement 1: m^5n^2<0
but n^2 is always positive for any non zero value of n hence
m^5 is Negative
i.e. m <0 but the sign of n is unknown hence
NOT SUFFICIENT
Statement 2: m^11*p^8*n^5<0
p^8 is always positive for any non zero value of p hence
m^11 * n*5 < 0
For odd powers the sign doesn't change
Hence, mn<0
SUFFICIENT
Answer: option B
