If the ages of students in a class vary between 18 and 22 inclusive, which of the following describes all possible ages x in this class?
(A) |x - 18|≤4
(B) |x + 20|≤2
(C) |x - 21|≤1
(D) |x - 22|≤0
(E) |x - 20|≤2
ages x in this class
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- sanju09
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- amising6
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out of the given optionsanju09 wrote:If the ages of students in a class vary between 18 and 22 inclusive, which of the following describes all possible ages x in this class?
(A) |x - 18|≤4
(B) |x + 20|≤2
(C) |x - 21|≤1
(D) |x - 22|≤0
(E) |x - 20|≤2
|x - 20|≤2
x-20≤2 so x ≤22
-(x-20) ≤2
-x+20 ≤2
18 ≤x
so option E
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- amising6
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selango wrote:The possible ages of X are 19,20,21,22.
If v substitute the values,option A alone satisfy the ineqaulity.
|x| <0
mod (x) <0 means x can either be +ve or -ve
means +x<0
-x<0
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- hardik.jadeja
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I couldn't understand what you are trying to say here.amising6 wrote:selango wrote:The possible ages of X are 19,20,21,22.
If v substitute the values,option A alone satisfy the ineqaulity.
|x| <0
mod (x) <0 means x can either be +ve or -ve
means +x<0
-x<0
I am still having hard time figuring out why A cannot be the right answer.
Could you please explain this again in detail?
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|a-b| just means how far apart a and b are on the number line.
The ages are between 18 and 22. Thus, the age of any person, x, can be at most 2 away from 20.
Thus, |x-20|<= 2
The ages are between 18 and 22. Thus, the age of any person, x, can be at most 2 away from 20.
Thus, |x-20|<= 2
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- hardik.jadeja
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Isnt the ineqaulity in option A also satisfied by the details given in the question?Testluv wrote:|a-b| just means how far apart a and b are on the number line.
The ages are between 18 and 22. Thus, the age of any person, x, can be at most 2 away from 20.
Thus, |x-20|<= 2
As you said, the ages are between 18 and 22 and the age of any person X can be at most 4 away from 18.
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hardik.jadeja wrote:Isnt the ineqaulity in option A also satisfied by the details given in the question?Testluv wrote:|a-b| just means how far apart a and b are on the number line.
The ages are between 18 and 22. Thus, the age of any person, x, can be at most 2 away from 20.
Thus, |x-20|<= 2
As you said, the ages are between 18 and 22 and the age of any person X can be at most 4 away from 18.
The inequality in option A dose satisfy the constraints given in question but if you try and plot it on a number line option A and option E will give you different results .
The question says the age should be between 18 and 22 inclusive .That means 18<= x <= 22 .
If you plot this on a number line only option E matches as it says 18<= x <= 22 .
Although the number line represented by option (A) 14<= x <= 22 covers the same range required by the question its is not the same graph what is required .
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- hardik.jadeja
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I wasn't aware that we have to keep graphs in mind while answering such questions.. The question just asked which of the following describes all possible ages x in this class.rockeyb wrote: The inequality in option A dose satisfy the constraints given in question but if you try and plot it on a number line option A and option E will give you different results .
The question says the age should be between 18 and 22 inclusive .That means 18<= x <= 22 .
If you plot this on a number line only option E matches as it says 18<= x <= 22 .
Is this one odd question where we need to consider graphs for picking the right answer or are there many similar questions?
- rockeyb
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Just one point to remember whenever faced with an INEQUALITY question + mod operator (||) its better to verify your answer on a number line . Gives you a clear idea .hardik.jadeja wrote:I wasn't aware that we have to keep graphs in mind while answering such questions.. The question just asked which of the following describes all possible ages x in this class.rockeyb wrote: The inequality in option A dose satisfy the constraints given in question but if you try and plot it on a number line option A and option E will give you different results .
The question says the age should be between 18 and 22 inclusive .That means 18<= x <= 22 .
If you plot this on a number line only option E matches as it says 18<= x <= 22 .
Is this one odd question where we need to consider graphs for picking the right answer or are there many similar questions?
No this is not one odd question I have seen such questions around so I think these kind of questions are normal. Well I am no expert in this case may be others can shed some light .
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