GMAT Data Sufficiency Discussions

MBA GMAT
1741
One more: Sorry if this is repost.

if x^2 + 5y = 49, is y an integer?
(1) 1 (2) x^2 is an integer.



Will go with C

1) x can be fractions ...not suff
2) x^2 = set of all integers .... not suff

1 & 2 )

x can be 2 or 3

when x = 2
y = 9

when x = 3
y = 8

combining 1 & 2 is sufficient
1742

Please solve the following

In a group of 6 people, the average (arithmetic mean) height of any two people in the group is less than 175 cm. How many people in the group have a height of 175 cm or greater?

(1) There is one person in the group who is 180 cm tall.
(2) The average height for the entire group is below 175

1743
Will go with C

1) x can be fractions ...not suff
2) x^2 = set of all integers .... not suff

1 & 2 )

x can be 2 or 3

when x = 2
y = 9

when x = 3
y = 8

combining 1 & 2 is sufficient


I think you missed on the condition where x=1.414 and x^2=2. the same for
x^2=3.

So the ans must be E.
1744
Please solve the following

In a group of 6 people, the average (arithmetic mean) height of any two people in the group is less than 175 cm. How many people in the group have a height of 175 cm or greater?

(1) There is one person in the group who is 180 cm tall.
(2) The average height for the entire group is below 175


IMO A.

from the info in the ques we know that avg height of any two individuals is
so from 1) we know that there is only 1 person in the group with height of 180. if there is one more person with a height > 175 then the avg will be > 175. so 1) alone is suff.

Now 2) we know that total sum of heights is
but we dont know whether we have a single person with a height above 175 or no person with a height above 175.

Hence insuff.

Please post the OA?
1745
Q2:
If 2 different representatives are to be selected at random from a group of 10 employees and if p is the probability that both representatives selected will be women, is p > 1/2 ?
(1) More than half of the 10 employees are women.
(2) The probability that both representatives selected will be men is less than 1/10


Although the problem was posted just 10 days back, I could not find the OA and my answer did not match with the answers arrived at by fellow puys.

My method goes like this.

Statement 1: (Not sufficient)
We can have 6, 7, 8, 9 women

6C2 / 10C2 = 0.33
However, 9C2 / 10C2 = 0.8

Since we get both the answers as 0.33
Statement 2: Sufficient

As the statement says that probability of both rep are men is less than 1/10. We can thus safely arrive that probability of both rep women is more than 1/2.

1/10 means less than 10%.

Thus for the probability of both rep women could be 90%, 91%, 92%, 93%..... which is more than 50%...

Dunno if i have overlooked something...:lookround:
1746
Please solve the following

In a group of 6 people, the average (arithmetic mean) height of any two people in the group is less than 175 cm. How many people in the group have a height of 175 cm or greater?

(1) There is one person in the group who is 180 cm tall.
(2) The average height for the entire group is below 175



Since the avg height of ANY two persons is less than 175,atmost we can have only one person whose height is >=175.

Statement1:
=========
This statement tells that the tallest person is 180cm and this will be only one person whose height > 175.This is suff.

Statement 2:
==========
Nt suff.
1747
Please solve the following

In a group of 6 people, the average (arithmetic mean) height of any two people in the group is less than 175 cm. How many people in the group have a height of 175 cm or greater?

(1) There is one person in the group who is 180 cm tall.
(2) The average height for the entire group is below 175


any 2 people in the have an average height less than 175

Statement 1 --> One person with height 180
So for average height of any 2 people to be less than 175 the height of all other people should be less than 170...... bcoz (170+180)/2=175
So only 1 person in the group has height greater than 175....
Sufficient

Statement 2 --> Average height of group is less than 175 . Dosent help in finding the solution

So IMO option A
What's the OA??
1748
Please solve the following

In a group of 6 people, the average (arithmetic mean) height of any two people in the group is less than 175 cm. How many people in the group have a height of 175 cm or greater?

(1) There is one person in the group who is 180 cm tall.
(2) The average height for the entire group is below 175



all of you nailed it ... OA is A
1749
Darth Maul Says
all of you nailed it ... OA is A


But i felt this was a tricky question.

1750
Although the problem was posted just 10 days back, I could not find the OA and my answer did not match with the answers arrived at by fellow puys.

My method goes like this.

Statement 1: (Not sufficient)
We can have 6, 7, 8, 9 women

6C2 / 10C2 = 0.33
However, 9C2 / 10C2 = 0.8

Since we get both the answers as 0.33
Statement 2: Sufficient

As the statement says that probability of both rep are men is less than 1/10. We can thus safely arrive that probability of both rep women is more than 1/2.

1/10 means less than 10%.

Thus for the probability of both rep women could be 90%, 91%, 92%, 93%..... which is more than 50%...

Dunno if i have overlooked something...:lookround:

probability of both mensuppose M=2, prob = 1/45 which isless than 1/10
M=3, prob = 1/30 which is less than 1/10
M=4 , prob= 1/7.5 , which is greater than 1/10 hence M= 2 or 3
now if M=2 them W=8 and p= 0.62
if M=3 then W=7 and P= 0.46 hence Not sufficient
combining 1& 2 also doesn't answer .
ans : E
1751
if p, s, and t are positive prime numbers, what is the value of p^3s^3t^3?
(1) p^3st=728
(2) t=13
1752
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.
1753
During a 10-week summer vacation, was the average (arithmetic mean) number of books that Carolyn read per week greater than the average number of books that Jacob read per week?

(1) Twice the average number of books that Carolyn read per week was greater than 5 less than twice the average number of books that Jacob read per week.
(2) During the last 5 weeks of the vacation, Carolyn read a total of 3 books more than Jacob.
1754
if p, s, and t are positive prime numbers, what is the value of p^3s^3t^3?
(1) p^3st=728
(2) t=13



IMo A

from 1) we have 2^3*7*13 so 1) alone is suff.

2) Not suff.
1755
During a 10-week summer vacation, was the average (arithmetic mean) number of books that Carolyn read per week greater than the average number of books that Jacob read per week?
(1) Twice the average number of books that Carolyn read per week was greater than 5 less than twice the average number of books that Jacob read per week.
(2) During the last 5 weeks of the vacation, Carolyn read a total of 3 books more than Jacob.


IMO E.

from 1) we have

2C > 2J-5, but from this eq we cannot acc determine whether C> J


from 2) we have only info on 5 weeks.

combining both we have no info on the values of c and J.
1756
if p, s, and t are positive prime numbers, what is the value of p^3s^3t^3?
(1) p^3st=728
(2) t=13

I assume question as (p^3)(s^3)(t^3)

Now.. Statement 1.
(p^3)st=728

factors of 728=8*7*13
So..p=2, s or t are 7 or 13
Hence sufficient IMO (A).
1757
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.


We need 5X+3Y/8

so from 1) we have x+y=10

so we have 2x+30/8 insuff

from 2) we have avg point value is integer so not suff

combining both we dont have any conclusive ans.

x= 5,9 and so on so E.
1758

I think I completely miscomprehended the questions.. thanks for ya explnation.. now I feel so silly :lookround:

OA is option A indeed.. thanks!! ;)

IMo A

from 1) we have 2^3*7*13 so 1) alone is suff.

2) Not suff.

I assume question as (p^3)(s^3)(t^3)
Now.. Statement 1.
(p^3)st=728
factors of 728=8*7*13
So..p=2, s or t are 7 or 13
Hence sufficient IMO (A).
1759
IMO E.

from 1) we have

2C > 2J-5, but from this eq we cannot acc determine whether C> J


from 2) we have only info on 5 weeks.

combining both we have no info on the values of c and J.


well.. I marked option E as well.. but thats not the OA..
1760

this doesnt match OA either.. :lookround: