DS - equation

[tomp]

Hy,

is d negative?

1. e + d = -12

2. e - d < -12


I say E, what do you think?

[VSG]

IMO C


1)e+d=-12
e=12
d= -24
and e=-24 d=12 so +ve or -ve insuff

2) similary to 1 we can prove d as +ve or -ve

now taken togeater

e-d<-12
add e+d to both side
2e<-24
e<-12
since e<-12 e could be -13,-14,-15...
to satisfy eq1
d>0
hence C

[hengirl03]

Originally Posted by VSG

IMO C


1)e+d=-12
e=12
d= -24
and e=-24 d=12 so +ve or -ve insuff

2) similary to 1 we can prove d as +ve or -ve

now taken togeater

e-d<-12
add e+d to both side
2e<-24
e<-12
since e<-12 e could be -13,-14,-15...
to satisfy eq1
d>0
hence C

I'm sorry, but i don't get the third part of your explanation.

[VSG]

e-d<-12...from statement 2

add e+d to both side
e-d<-12
e-d+e+d<-12+e+d
2e<-12+(e+d)
from statement 1
2e<-12-12
2e<-24
e<-12---devide both side by 2


since e<-12 e could be -13,-14,-15...
to satisfy statement 1(e+d=-12)
d>0
hence C