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# gmatbusters' challenge questions

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Manager
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Joined: 07 Jun 2018
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23 Jun 2018, 07:57
gmatbusters wrote:
Six blocks shown below are to be rearranged so that the letters are in alphabetical order, reading from left to right. What is the minimum number of blocks that must be moved to arrive at the desired arrangement?
Attachment:
gmatbusters.jpg

A) 2
B) 3
C) 4
D) 5
E) 6

I think B
1) A C B E F D
2) A B C E F D
3) A B C D E F

the answer will change if we have to interchange the blocks. Then the ans will be 4. There can be various ways to solve then.
1) A B E F D C
2) A B C F D E
3) A B C D F E
4) A B C D E F
but as the question demands moving the blocks first approach needs to be followed i think, thus answer is 3

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03 Jul 2018, 17:46
1
At the Canterbury Dog Fair, 1/4 of the poodles are also show dogs and 1/7 of the show dogs are poodles. What is the least possible number Of dogs at the fair?
A) 10
B) 11
C) 15
D) 25
E) 70

Spoiler: :: OA
A

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12 Jul 2018, 10:15
1
1
Let the number of Canterbury dogs = C
and number of show dogs = S
now, C/4 = S/7
For min value of total dogs, min value of C = 4, min value of S = 7.
now the min value of total no of dogs = number of Canterbury dogs+ number of show dogs- Common dogs
= 4+7-1 = 10

gmatbusters wrote:
At the Canterbury Dog Fair, 1/4 of the poodles are also show dogs and 1/7 of the show dogs are poodles. What is the least possible number Of dogs at the fair?
A) 10
B) 11
C) 15
D) 25
E) 70

Spoiler: :: OA
A

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Is the slope of line m passing through (7,4) positive?  [#permalink]

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12 Jul 2018, 10:22
1
Is the slope of line m passing through (7,4) positive?
1) The line m makes an angle of 30 deg with x-axis.
2) The y-intercept of line m is 2.

Spoiler: :: OA
B

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13 Jul 2018, 09:39
1
gmatbusters wrote:
Is the slope of line m passing through (7,4) positive?
1) The line m makes an angle of 30 deg with x-axis.
2) The y-intercept of line m is 2.

Spoiler: :: OA
B

Statement 1) The line $$m$$ makes an angle of 30 degrees with the x-axis
We have no idea whether the angle is formed this way / or this way \
Insufficient.

Statement 2) The y-intercept of line m is 2.
Two points now: (0,2) and (7,4)
We have enough information to determine whether the slope is positive or negative.
(No need to calculate, but slope is $$\frac{2}{7}$$)
Sufficient.

Attachment:

DSslope 2018.07.13.jpg [ 61.89 KiB | Viewed 2009 times ]

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17 Jul 2018, 03:00
Barui drives a certain part of his journey at an average speed of 30 miles per hour and the rest at an average speed of 60 miles per hour. If he drives for 100 miles, is his average speed for the journey greater than 45 miles per hour?

(1) Had Barui driven at an average speed of 80 miles per hour rather than 30 miles per hour, his average speed for the journey would have been more than 68 miles per hour.

(2) Had Barui driven at an average speed of 40 miles per hour rather than 30 miles per hour, his average speed for the journey would have been less than 48.5 miles per hour.

Spoiler: :: OA
D

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12 Aug 2018, 07:27
The average of a couple was 24 year when the child was just born. What will be the age of the father when the child reaches to the age of the mother when she gave him the birth?
A) 24
B) 36
C) 48
D) 60
E) cannot be determined
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12 Aug 2018, 08:33
1
gmatbusters wrote:
The average of a couple was 24 year when the child was just born. What will be the age of the father when the child reaches to the age of the mother when she gave him the birth?
A) 24
B) 36
C) 48
D) 60
E) cannot be determined

+1 for C

Let mother age be m and father age be f when child was born.

So, according to question m+f = 48

Now child age has increased by m, so father age will also increase by m

Hence father age = m+f = 48.

Correct me if I am wrong.
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12 Aug 2018, 08:36
you are right.

arun6765 wrote:
gmatbusters wrote:
The average of a couple was 24 year when the child was just born. What will be the age of the father when the child reaches to the age of the mother when she gave him the birth?
A) 24
B) 36
C) 48
D) 60
E) cannot be determined

+1 for C

Let mother age be m and father age be f when child was born.

So, according to question m+f = 48

Now child age has increased by m, so father age will also increase by m

Hence father age = m+f = 48.

Correct me if I am wrong.

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29 Aug 2018, 11:12
#DS CHALLENGING QUESTION OF THE DAY

If ABCD is a parallelogram with AB=21 BC=13 . What is the value of AC?
1) BD=14
2) AO=16, where O is the point of intersection of diagonals.
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29 Aug 2018, 11:23
1
gmatbusters wrote:
#DS CHALLENGING QUESTION OF THE DAY

If ABCD is a parallelogram with AB=21 BC=13 . What is the value of AC?
1) BD=14
2) AO=16, where O is the point of intersection of diagonals.

Not that challenging to be honest.

Option (B).

- Statement 1 gives us info about the other diagonal. Not suff.

- Statement 2 is sufficient as Diagonals of a parallelogram bisect each other.
Hence if AO = 16, AC = 32.

Regards,
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29 Aug 2018, 12:45
gmatbusters wrote:
#DS CHALLENGING QUESTION OF THE DAY

If ABCD is a parallelogram with AB=21 BC=13 . What is the value of AC?
1) BD=14
2) AO=16, where O is the point of intersection of diagonals.
Diagonals bisect each other in parallelogram. Looks like answer is B

Thank you = Kudos
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29 Aug 2018, 17:35
You have proved it...the OA is D.

It is not that easy.

gmatbusters wrote:
#DS CHALLENGING QUESTION OF THE DAY

If ABCD is a parallelogram with AB=21 BC=13 . What is the value of AC?
1) BD=14
2) AO=16, where O is the point of intersection of diagonals.

Not that challenging to be honest.

Option (B).

- Statement 1 gives us info about the other diagonal. Not suff.

- Statement 2 is sufficient as Diagonals of a parallelogram bisect each other.
Hence if AO = 16, AC = 32.

Regards,

Posted from my mobile device
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29 Aug 2018, 23:07
gmatbusters wrote:
You have proved it...the OA is D.

It is not that easy.

gmatbusters wrote:
#DS CHALLENGING QUESTION OF THE DAY

If ABCD is a parallelogram with AB=21 BC=13 . What is the value of AC?
1) BD=14
2) AO=16, where O is the point of intersection of diagonals.

Not that challenging to be honest.

Option (B).

- Statement 1 gives us info about the other diagonal. Not suff.

- Statement 2 is sufficient as Diagonals of a parallelogram bisect each other.
Hence if AO = 16, AC = 32.

Regards,

Posted from my mobile device
Hi gmatbusters,

TIA

Thank you = Kudos
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30 Aug 2018, 06:23
sumit411,

In Geometry DS Question, Visualization is the key...
Attachment:

WhatsApp Image 2018-08-30 at 18.50.19.jpeg [ 68.9 KiB | Viewed 1694 times ]

gmatbusters wrote:
#DS CHALLENGING QUESTION OF THE DAY

If ABCD is a parallelogram with AB=21 BC=13 . What is the value of AC?
1) BD=14
2) AO=16, where O is the point of intersection of diagonals.

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19 Oct 2019, 20:05
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Re: gmatbusters' challenge questions   [#permalink] 19 Oct 2019, 20:05

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