GMAT Data Sufficiency Discussions

Q1: Are x and y both positive?
1) 2x-2y=1
2) x/y >1

C

Q2: Is m+z>0 ?
1) m-3z>0
2) 4z-m>0

E

Q3: If integers a and n are greater than 1 and the product of the first 8 positive integers is a multiple of an, what is the value of a?
1) an = 64 2) n = 6
E

Q4: What is the remainder when posiytive integer x is divided by 6?
1) When x is divided by 2, the remainder is 1; and when x is divided by 3, the remainder is 0.( try numbers 9,13)
2) When x is divided by 12, the remainder is 3.

B

Q5: At a certain company, average (aritmetic mean) number of years of experience is 9.8 years for male employees and 9.1 years for female employees. What is the ratio of the number of company's male employees to the number of company's female employees?
1) There are 52 male employees at the company.
2) Average number of years of experience for the company's male and female employees combined is 9.3 years.
C




If right will post explanations.
Q1: Are x and y both positive?
1) 2x-2y=1
2) x/y >1

Q2: Is m+z>0 ?
1) m-3z>0
2) 4z-m>0

Q3: If integers a and n are greater than 1 and the product of the first 8 positive integers is a multiple of an, what is the value of a?
1) an = 64 2) n = 6

Q4: What is the remainder when posiytive integer x is divided by 6?
1) When x is divided by 2, the remainder is 1; and when x is divided by 3, the remainder is 0.
2) When x is divided by 12, the remainder is 3.

Q5: At a certain company, average (aritmetic mean) number of years of experience is 9.8 years for male employees and 9.1 years for female employees. What is the ratio of the number of company's male employees to the number of company's female employees?
1) There are 52 male employees at the company.
2) Average number of years of experience for the company's male and female employees combined is 9.3 years.




reasonong for sum 4 and sum 5 :

Prob 4:

we need to epress the no in the form 6k+m, where k and m are integer values and we need one definite value for m..

St 1 : no is odd multiple of 3 ....hence of the form 6k+3 ...one definite remainder 3 ...hence sufficient..

St2: no is of the form 12p+3 i .e 6*2*p +3 i.e 6k+3 ( where k =2p)...hence again one def remainder 3 ...sufficient ...

Hence, Ans D

Prob 5:

let there be x male and y female employees..
so, total experience = 9.8x +9.1y...
we need one more equation to get values of x and y for a specific ratio of x/y

St 1: x =52....still neither we dont know the total employee strength nor total experience...not suff..

St 2: total experience = 9.3 (x+y)
so, 9.3 (x+y) = 9.8x +9.1y..
Hence, x/y = 2/5 ...suff

Hence, Ans B...

I was about to put my explanation for 5th problem as I felt C is not the right answer. Glad that you found the mistake in your earlier post all by yourself.

What is the value of x + y in the figure above?
(1) w = 95
(2) z = 125

What is the value of x + y in the figure above?

(1) w = 95
(2) z = 125

hello ramwiswa...

supplementary angles of w,x,y,z form a quadrilateral
i.e (180-w) + (180-x) + (180-y) + (180-z) = 360
i.e w+x+y+z = 360

individual statements not suff....

combined ok ...i.e x+y = 140

Hence, Ans C

Thanks for the explanation. Your answers are correct except for Q3 which had a typo. The question goes as below:
Q3: If integers a and n are greater than 1 and the product of the first 8 positive integers is a multiple of an, what is the value of a?
1) a^n = 64 2) n = 6
Can you please give your answer and explanation?

Thanks for the explanation. Your answers are correct except for Q3 which had a typo. The question goes as below:
Q3: If integers a and n are greater than 1 and the product of the first 8 positive integers is a multiple of an, what is the value of a?
1) a^n = 64 2) n = 6
Can you please give your answer and explanation?


from stat one

a^n=64

so possible value for 64=2^6 / 4^3 / 8^2

now an is multiple of 40320 so possible value for a^n anything out of 3(2^6 / 4^3 / 8^2) because 12,12,16 all r multiple of 40320

so 1 st not possible

from 2nd one

n=6

from 2 u cant say anything because 40320/6=6720

so value of A could be anyone of the factor of 6720

but if we take both to gather we will get 2^6 ans........


ans C as per typical ans option format

But the OA is B. I still believe C is correct as you explained.

Is MNP isosceles?(1)Exactly two of the angles, (2)

srworld Says
Is MNP isosceles?(1)Exactly two of the angles, (2)



from statement 1


angle M & N same measure

if angle P is different then it will became isosceles but if M=N=P then it will became equilateral

so from 1 its not sufficient

from statement 2

N & P not same

so may be M & N same or different.... or M & P same or different

so its not sufficient

combining both

M=N but N not equal to P

so its isosceles

option C

But statement 1 says...Exactly two angles. Doesn't that implies that its saying that only 2 angles measures the same?

srworld Says
But statement 1 says...Exactly two angles. Doesn't that implies that its saying that only 2 angles measures the same?


yep than ans is option A
jigar_p_civil Says
yep than ans is option A


I think, Equilateral triangle can also be called as Isosceles triangle.
ramviswa Says
I think, Equilateral triangle can also be called as Isosceles triangle.


though all squares are recatangles, all rhombus are parallelogram and all congruent triangles are similar, i dont think equilateral triangle can be called as an isosceles triangle ...

Def of isosceles i presume is exactly 2 sides equal and not atleast 2 sides equal ...
ramviswa Says
I think, Equilateral triangle can also be called as Isosceles triangle.


Isosceles means ONLY 2 sides equal.. and Equilateral means ALL sides equal in length..

Isosceles is NOT same as Equilateral.. or vice versa..

I am not saying Isoscles triangle is equilateral triangle. What am saying is Equilateral triangle is an isosceles triangle with the third angle (first two angles are equal equal) equal to 60.

I can easily put this as a DS question.

I believe that DS question if appears simple it means there is a catch similiar to the above question.We can not take isosceles with equilateral triangle here although equ.. triangle satisfies all properties of isc.

Thanks for the explanation. Your answers are correct except for Q3 which had a typo. The question goes as below:
Q3: If integers a and n are greater than 1 and the product of the first 8 positive integers is a multiple of an, what is the value of a?
1) a^n = 64 2) n = 6
Can you please give your answer and explanation?

If just 1 is used, (a,n) can be (2,6) , (4,3), (8,2). So a can have any value out of 2,4 or 8.

If statement 2 alone is used, a can have any values from 2, 3, 4, 5, 6, 7, 8. ..

If both statement 1 and 2 are used, as value will be 2.

So the answer is C.
srworld Says
Is MNP isosceles?(1)Exactly two of the angles, (2)



1 alone is sufficient to answer the question.

If two angles of the triangle are equal, the triangle has to be isosceles or equilateral (if all the angles are equal).
Even if all the angles are equal, the triangle is equilateral and an equilateral triangle is isosceles.

2 alone cannot answer the question. if two angles of a triangle are not equal, the triangle still can be isosceles, if the other two angles are same. So we cannot answer for sure whether the triangle is isosceles or not.

So the answer is A.
I am not saying Isoscles triangle is equilateral triangle. What am saying is Equilateral triangle is an isosceles triangle with the third angle (first two angles are equal equal) equal to 60.

I can easily put this as a DS question.


I agree with you Ramviswa,

An equilateral triangle is an isosceles triangle with the third side equal to the other two.