DS001
If x is positive, is x>3?
a) (x-1)^2 > 4
b) (x-2)^2 > 9
A) a alone b not sufficient
B) b alone a not sufficient
C) both together but not alone sufficient
D) each alone sufficient
E) together not sufficient
Answers In 3 days of time
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E.
First case leads to x > 3 or x > -1 => insufficient
Second case leads to x > 5 or x > -1 => insufficient
Both together is still inconclusive x could be a positive number greater or less or equal to 3.
First case leads to x > 3 or x > -1 => insufficient
Second case leads to x > 5 or x > -1 => insufficient
Both together is still inconclusive x could be a positive number greater or less or equal to 3.
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Jeff,
Consider (x-1)^2 > 4
which will mean (x-1)^2-4>0
((x-1)+2)((x-1)-2)>0 [using the identity a^2-b^2 =(a+b)(a-b)]
Simplifying,
(x+1)(x-3)>0
now for a product of two terms {(x+1),(x+3)} to be positive
either both x+1 and x-3 to be postive which is possible only when x>3
or both x+1 and x-3 to be negative which is possible only when x<-1
so we can safely conclude that (x-1)^2 > 4 will mean x>3 or x<-1
moving on similar lines we can solve the other inequality also ...
Revert back to me if you have any doubts on this.
As promised, answers in 3 days of time
Consider (x-1)^2 > 4
which will mean (x-1)^2-4>0
((x-1)+2)((x-1)-2)>0 [using the identity a^2-b^2 =(a+b)(a-b)]
Simplifying,
(x+1)(x-3)>0
now for a product of two terms {(x+1),(x+3)} to be positive
either both x+1 and x-3 to be postive which is possible only when x>3
or both x+1 and x-3 to be negative which is possible only when x<-1
so we can safely conclude that (x-1)^2 > 4 will mean x>3 or x<-1
moving on similar lines we can solve the other inequality also ...
Revert back to me if you have any doubts on this.
As promised, answers in 3 days of time
Last edited by ajith on Mon Oct 30, 2006 9:54 pm, edited 2 times in total.
- ajith
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I think you have made a mistake there rajs.kumar,rajs.kumar wrote:E.
First case leads to x > 3 or x > -1 => insufficient
Second case leads to x > 5 or x > -1 => insufficient
Both together is still inconclusive x could be a positive number greater or less or equal to 3.
is it x > -1 or x<-1 ?
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DS002
What is the value of (2a+b)/(a+b)?
(1) 3a/(a+b) = 7
(2) a+b = 3
A) 1 alone b not sufficient
B) 2 alone a not sufficient
C) both together but not alone sufficient
D) each alone sufficient
E) together not sufficient
Answers In 3 days of time,
Hereafter, when you reply , either quote the question or reply with the question number as there can be overlap.
Thanks,
Ajith
What is the value of (2a+b)/(a+b)?
(1) 3a/(a+b) = 7
(2) a+b = 3
A) 1 alone b not sufficient
B) 2 alone a not sufficient
C) both together but not alone sufficient
D) each alone sufficient
E) together not sufficient
Answers In 3 days of time,
Hereafter, when you reply , either quote the question or reply with the question number as there can be overlap.
Thanks,
Ajith
- limits660
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Yes, i see it now. Thanks very much on the detailsajith wrote:Jeff,
Consider (x-1)^2 > 4
which will mean (x-1)^2-4>0
((x-1)+2)((x-1)-2)>0 [using the identity a^2-b^2 =(a+b)(a-b)]
Simplifying,
(x+1)(x-3)>0
now for a product of two terms {(x+1),(x+3)} to be positive
either both x+1 and x-3 to be postive which is possible only when x>3
or both x+1 and x-3 to be negative which is possible only when x<-1
so we can safely conclude that (x-1)^2 > 4 will mean x>3 or x<-1
moving on similar lines we can solve the other inequality also ...
Revert back to me if you have any doubts on this.
As promised, answers in 3 days of time
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ajith wrote:DS001
If x is positive, is x>3?
a) (x-1)^2 > 4
b) (x-2)^2 > 9
A) a alone b not sufficient
B) b alone a not sufficient
C) both together but not alone sufficient
D) each alone sufficient
E) together not sufficient
Answers In 3 days of time
3 days are over!
When we solve a we get x>3 or x<-1(refer the above post for explanation)
since x is positive , x>3
So a is sufficient to answer
now conisdering b
(x-2)^2 > 9
=>(x-2+3)(x-2-3)>0
upon solving which we get x>5 or x<-1
since x is positive , x>5
So b is sufficient to answer
so the answer is D. Both alone are sufficient
Always borrow money from a pessimist, he doesn't expect to be paid back.
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DS003
How many people are in the second car in a line of three cars?
1. The total number of people in the three cars is one more than the total number of people in the first and third car.
2. There are a total of 7 people in the three cars.
A) 1 alone b not sufficient
B) 2 alone a not sufficient
C) both together but not alone sufficient
D) each alone sufficient
E) together not sufficient
:roll:
How many people are in the second car in a line of three cars?
1. The total number of people in the three cars is one more than the total number of people in the first and third car.
2. There are a total of 7 people in the three cars.
A) 1 alone b not sufficient
B) 2 alone a not sufficient
C) both together but not alone sufficient
D) each alone sufficient
E) together not sufficient
:roll:
Always borrow money from a pessimist, he doesn't expect to be paid back.
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I figured where I went wrong. thanks.ajith wrote:I think you have made a mistake there rajs.kumar,rajs.kumar wrote:E.
First case leads to x > 3 or x > -1 => insufficient
Second case leads to x > 5 or x > -1 => insufficient
Both together is still inconclusive x could be a positive number greater or less or equal to 3.
is it x > -1 or x<-1 ?
(x-1) ^ 2 > 4 => x-1 > 2 or x-1 < -2 and I missed the x is positive. Overlooked.
Last edited by rajs.kumar on Fri Nov 03, 2006 1:20 am, edited 1 time in total.
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x = a+b => (a + x)/x =ajith wrote:DS002
What is the value of (2a+b)/(a+b)?
(1) 3a/(a+b) = 7
(2) a+b = 3
A) 1 alone b not sufficient
B) 2 alone a not sufficient
C) both together but not alone sufficient
D) each alone sufficient
E) together not sufficient
Answers In 3 days of time,
Hereafter, when you reply , either quote the question or reply with the question number as there can be overlap.
Thanks,
Ajith
1. 3a/x = 7 => a = 7x/3
7x/3/x + 1 => suff
2. a+b = 3 = x
(a+3)/3 => insuff
Answer is A.
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Answer is A.ajith wrote:DS003
How many people are in the second car in a line of three cars?
1. The total number of people in the three cars is one more than the total number of people in the first and third car.
2. There are a total of 7 people in the three cars.
A) 1 alone b not sufficient
B) 2 alone a not sufficient
C) both together but not alone sufficient
D) each alone sufficient
E) together not sufficient
:roll:
A+B+C = A+C+1 => suff
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A baby!ajith wrote:DS003
How many people are in the second car in a line of three cars?
1. The total number of people in the three cars is one more than the total number of people in the first and third car.
2. There are a total of 7 people in the three cars.
A) 1 alone b not sufficient
B) 2 alone a not sufficient
C) both together but not alone sufficient
D) each alone sufficient
E) together not sufficient
:roll:
Im pretty sure I got this one
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DS002
What is the value of (2a+b)/(a+b)?
(1) 3a/(a+b) = 7
(2) a+b = 3
A) 1 alone b not sufficient
B) 2 alone a not sufficient
C) both together but not alone sufficient
D) each alone sufficient
E) together not sufficient
Ans:
3a/(a+b)=7
=>a/a+b=7/3
=> 1+a/a+b=1+7/3
=>2a+b/a+b=10/7
so 1 is sufficient
it's evident that 2 is not by itself sufficient
so
A
What is the value of (2a+b)/(a+b)?
(1) 3a/(a+b) = 7
(2) a+b = 3
A) 1 alone b not sufficient
B) 2 alone a not sufficient
C) both together but not alone sufficient
D) each alone sufficient
E) together not sufficient
Ans:
3a/(a+b)=7
=>a/a+b=7/3
=> 1+a/a+b=1+7/3
=>2a+b/a+b=10/7
so 1 is sufficient
it's evident that 2 is not by itself sufficient
so
A
Always borrow money from a pessimist, he doesn't expect to be paid back.