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what is the value for a-b

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what is the value for a-b

by elaine1920 » Fri Jul 17, 2009 1:14 pm
If a and b are integers and a is even, what is the value of a-b?
1) a<3
2) a/b=2/7

a) statement a is right
b) statemetn b is right
c) a and b together
d) either on
e) none

The answer is e

I was thinking about answer c. Since a is less than 3, the choice of a would be 0 or 2. And to combine the sec option, only when a=2 could result the faction. But the answer told me otherwise. Anyone could help me with this? thanks!

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you said it

by brick2009 » Fri Jul 17, 2009 1:33 pm
you know the answer..;-)

If "a" can have two values, 0 and 2, b will have two values.. hence a-b is not unique.. hence cant answer..E

looks like you zoned out there..buddy..;-)
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by elaine1920 » Fri Jul 17, 2009 1:39 pm
haha thanks! But I was thinking that if the ratio of a/b=2/7, then that means a couldn't be 0. Am I overthinking too much? :D
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by woo » Fri Jul 17, 2009 5:21 pm
you have to think also about negative even numbers such as -2, -4..

That's why...
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by gmat740 » Fri Jul 17, 2009 5:45 pm
1) a<3
a= 2, -2, -4 etc. So can't say from Here
2) a/b=2/7
a=2 & b=7
but a=4 & b=14
likewise variety of combinations are possible. So insuff.

Combine Both

a=2 & b=7

so, a-b = 2-7 = -5

but hey,
a=-2 & b=-7
so,a-b = -2 +7 =5

So we are getting different answers.

Hence E
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