What is the source of this question? I'm getting E ....
for instance a = -2 and c = 4 b cannot be 2. this fulfill statements 1 and 2
Let's say b = 6 |-2| = 6 -4 true
let's say b= 7 |-2| = 7 -4 false
algebra ds
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mikeCoolBoy
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mikeCoolBoy
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- Joined: Tue Jan 20, 2009 10:16 pm
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if you change the statement 1 the answer is C.nitya34 wrote:OG had same prob except the "NE" part
C is perfect
shilpi84 wrote:Is |a| = b - c ?
(1) a + c NE(not equal) b
(2) a < 0
OA:C
Here is the logic.
First step rephrase the question
Is |a| = b - c ?
if you have absolute value you have to consider several cases
first what is inside the absolute value is positive. In our case a >0
second what is inside the absolute value is negative. In our case a < 0
third what is inside the absolute value is 0. In our case a = 0
rewriting the equations
a > 0 ---> a = b - c
a < 0 ----> a = c-b
a = 0 ----> b = c
now take a look at the statements
1)
a + c = b ---> a = b - c
is this sufficient to assure that |a| = b -c? no because a = b -c only if a < 0
not sufficient
2) a < 0 tells nothing about b and c. not sufficient
both together
a < 0 and a = b - c, this is just one of the equations of the rephrasing. so is sufficient
