IF zt< -3, is z<4?
1) z<9
2) t<-4
OA is E, I picked B
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givemeanid
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1. z<9
z=3, t=-6. z<4. True
z=6, t=-6. z>4. False
INSUFFICIENT.
2. t<-4
z=3, t=-6. z<4. True
z=6, t=-6. z>4. False
INSUFFICIENT.
Combining:
Same values as used above.
INSUFFICIENT.
Answer is (E).
z=3, t=-6. z<4. True
z=6, t=-6. z>4. False
INSUFFICIENT.
2. t<-4
z=3, t=-6. z<4. True
z=6, t=-6. z>4. False
INSUFFICIENT.
Combining:
Same values as used above.
INSUFFICIENT.
Answer is (E).
So It Goes
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jayant.apte
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The OA is E but I don't understand why the answer is not B. I think we should be able to take (2) and plug in values into zt < -3.
Using (2) say t = -6, we will get z x -6 < -3 which means z < 0.5 which is less than 4. Any value of t < -4 will result in z < 4 being satisfied. Am I missing something here?
Using (2) say t = -6, we will get z x -6 < -3 which means z < 0.5 which is less than 4. Any value of t < -4 will result in z < 4 being satisfied. Am I missing something here?
It actually means z > 0.5, not z < 0.5.
When dividing by a negative number, you need to flip the sign of the inequality.
You can choose some numbers for peace of mind:
Assume z < 0.5
Choose z = 0
0 * -6 < -3
0 < -3 is not true
Assume z > 0.5
Choose z = 0
1* -6 < -3
-6 < -3 is true
When dividing by a negative number, you need to flip the sign of the inequality.
You can choose some numbers for peace of mind:
Assume z < 0.5
Choose z = 0
0 * -6 < -3
0 < -3 is not true
Assume z > 0.5
Choose z = 0
1* -6 < -3
-6 < -3 is true
