GMAT Data Sufficiency Discussions

MBA GMAT
1781
Material A costs $3 per kilogram, and material B costs $5 per kilogram. If 10 kilograms of material K consists of x kilograms of material A and y kilograms of material B, is x > y?
(1) y > 4
(2) The cost of the 10 kilograms of material K is less than $40.



Ans B

1 is not suff. case 5,5 and 4,6 gives diff ans.

2.
3x + 5y only holds true for y=6..
in all these cases x > y
hence 2 is suff.
1782

My take for the below q is option C.Both the statements are reqd to ans the q

in a certain game played with red chips and blue chips, each red chip has a point value of X and each blue chip has a point value of Y, where X>Y and X and Y are positive integers. If a player has 5 red chips and 3 blue chips, what is the average (arithmetic mean ) point value of the 8 chips that the player has?


(1) The average point value of one red chip and one blue chip is 5.
(2) The average point value of the 8 chips that the player has is an integer.

1783
My take for the below q is option C.Both the statements are reqd to ans the q

in a certain game played with red chips and blue chips, each red chip has a point value of X and each blue chip has a point value of Y, where X>Y and X and Y are positive integers. If a player has 5 red chips and 3 blue chips, what is the average (arithmetic mean ) point value of the 8 chips that the player has?
(1) The average point value of one red chip and one blue chip is 5.
(2) The average point value of the 8 chips that the player has is an integer.




From X>Y and statement 1 . we get the following cases X=6, 4=4
X=7, Y=3
X=8, Y=2
X=9, Y=1

Now considering that there are 5 Red chips and 3 Blue chips and statement 2 which says mean value is an integer. We get only one case i.e X=9, Y=1.

Using both equations we can answer the question. So the answer is C
1784
My take for the below q is option C.Both the statements are reqd to ans the q

in a certain game played with red chips and blue chips, each red chip has a point value of X and each blue chip has a point value of Y, where X>Y and X and Y are positive integers. If a player has 5 red chips and 3 blue chips, what is the average (arithmetic mean ) point value of the 8 chips that the player has?


(1) The average point value of one red chip and one blue chip is 5.
(2) The average point value of the 8 chips that the player has is an integer.


you are correct deepak...
1785

Solve this

X,Y > 0 ,If X^3 = Y, is Y a fraction?

(1) X^2 is a fraction
(2) X >Y

^ = power

1786

IMO D. Did in haste. whats the oA?

1. x^2 is a fraction. This means x is a fraction too.
for example lets say x^2 = a/b where a,b are int and b>a
x=sqrt(a)/sqrt(b) . since a>b, x has to be a fracton.

now x^3=x^2*x multiplying 2 fractions will always lead to a fraction. there fore Y is a fraction. Sufficient

2. x > y
its given that x^3 = y.
any positive raised to a postive power will yield more value if the integer is >1

since x^3 equals y when x>y, it means that x is also, y

Solve this

X,Y > 0 ,If X^3 = Y, is Y a fraction?

(1) X^2 is a fraction
(2) X >Y

^ = power

1787
Solve this

X,Y > 0 ,If X^3 = Y, is Y a fraction?

(1) X^2 is a fraction
(2) X >Y

^ = power



IMO E. Please post the OA?
1788

Can you share your reasoning too? Thanks!

siddharthaduggirala Says
IMO E. Please post the OA?
1789
Solve this

X,Y > 0 ,If X^3 = Y, is Y a fraction?

(1) X^2 is a fraction
(2) X >Y

^ = power



(1) X^2 is a fraction --> e.g. X^2=1/4 =>x=1/2 hence x^3=1/8 a fraction - SUFFICIENT

(2) X>Y --> Given X^3 = Y Now
e.g X=3 , Y=3^3=9 => X X>Y (condition satisfied)
- SUFFICIENT
=> For Any numbers cube/sqr to be less than the number itself, Original number has to be a fraction betn (0,1)
1790
Solve this

X,Y > 0 ,If X^3 = Y, is Y a fraction?

(1) X^2 is a fraction
(2) X >Y

^ = power

IMO : B

Let us know the OA.
1791
Material A costs $3 per kilogram, and material B costs $5 per kilogram. If 10 kilograms of material K consists of x kilograms of material A and y kilograms of material B, is x > y?
(1) y > 4
(2) The cost of the 10 kilograms of material K is less than $40.


(1) y>4
x y (for x+y=10)
5 5
4 6
3 7
2 8
1 9
0 10
meaning xNOT SUFFICIENT

(2) value x y (for 3x+5y10 0
9 1
8 2
7 3
6 4
Here (5,5) is eliminated as it gives 3*5+5*5=40
meaning x>y hence SUFFICIENT

ANSWER:B
1792
IMO : B

Let us know the OA.


Could you Please give your reasoning
1793
nuttyvarun Says
nope.. the OA is not option E...


Could you please post the explanation?
I am not sure if the OA is correct. There is no info about the books read in the first half of the vacation. I would go for E

Can we make some sense out Cavg>Javg- 25/10?
1794

Is X a negative number?

1) X^2 is a poistive number
2) x.Y is not a positive number...

I know it looks straight but I've answer as E), can someone explain please?

1795
Is X a negative number?

1) X^2 is a poistive number
2) x.Y| is not a positive number...

I know it looks straight but I've answer as E), can someone explain please?



Here 1) is self explanatory.

for 2) x.|y can be zero since 0 is neither -ve nor +ve.

Even combining both sts we dont have a condition that y is a non-zero number. So E.
1796
Is X a negative number?

1) X^2 is a poistive number
2) x.Y| is not a positive number...

I know it looks straight but I've answer as E), can someone explain please?


1) x^2 is +ve #==> x is +ve or -ve

2)x.|y is not +ve # ==> x is zero or -ve

1 & 2 ==> x is -ve , Hence option C
1797
1) x^2 is +ve #==> x is +ve or -ve

2)x.y is not +ve # ==> x is zero or -ve

1 & 2 ==> x is -ve , Hence option C





My Answer is E :

taking 1) X can be +ve or -ve
taking 2) Y not equal to 0, X can be 0 or -ve,,,,, but in case Y=0, X can be
+ve or -ve or 0,,
so even with combining 1) and 2),, we cannot say x is +ve or -ve
1798
Is X a negative number?

1) X^2 is a poistive number
2) x.Y| is not a positive number...

I know it looks straight but I've answer as E), can someone explain please?


Statement 1: x^2 is postive... NOT SUFF since we know every number's sqare is positive only..

Statement 2: X.Y is not a positive number
|Y = always positive..
hence X can be either -ve or 0..
NOT SUFF

Combining 2 statements..
X comes out to be a negative number.. hence answer must be option C
1799
Is X a negative number?

1) X^2 is a poistive number
2) x.Y is not a positive number...

I know it looks straight but I've answer as E), can someone explain please?


Statement 1:
==========
X can be + or - . Nt suff

Statement 2:
===========
X can be + , - or 0 depending on the value of Y.Nt suff

Combining both we can arrive at a conclusion.So my take on the above DS is option E
1800
Is X a negative number?

1) X^2 is a poistive number
2) x.Y is not a positive number...

I know it looks straight but I've answer as E), can someone explain please?



Answer is E)..