Hi All,
Please suggest a method to solve this.
If x, y and z are integers greater than 1, and (3^27)(5^10)(z) = (5^
(9^14)(x^y), then what is the value of x?
(1) y is prime
(2) x is prime
My approach
Taking LHS into consideration,
(3^27)(5^10) =(5^(9^14)*3*(5^2)*(9^-1)
hence, z = 3*(5^2)*(9^-1) = 25/3 = (5^2)(3^-1)
Hereafter, I have no clue how to use the options given.
Please advice.
Yogi.
The numbers x and y are not integers.The value of x is closest to which integer?
1. 4 is the integer closest to x + y.
2. 1 is the integer closest to x - y
IMO ..Ans E
St 1 : 3.5
St 2 : 0.5
Combined : add , hence 4
Ans E
If k is a positive integer, is k the square of an integer?
1. k is divisible by 4
2. k is divisible by exactly 4 different prime numbers
A perfect square always has odd no of factors ..
St1: k = 4m ...every multiple of 4 is not a perfect square ..not suff..
St2 : it says 4 different prime factors, says nothing about total factors ..
Hence, k = a^m * b^n * c^p * d^s ...where a,b,c,d are prime nos ...
gives us nothing ...not suff..
Combined : we just know a^m = 2^2 ...nothing about other 3 prime factors and their powers , hence not suff...
IMO, Ans E
Hi All,
Please suggest a method to solve this.
If x, y and z are integers greater than 1, and (3^27)(5^10)(z) = (5^(9^14)(x^y), then what is the value of x?
(1) y is prime
(2) x is prime
My approach
Taking LHS into consideration,
(3^27)(5^10) =(5^
hence, z = 3*(5^2)*(9^-1) = 25/3 = (5^2)(3^-1)
Hereafter, I have no clue how to use the options given.
Please advice.
Yogi.
Yogesh, Ans for this one should be B ...
This question has already been posted some time back ..
Check the discussion here :
http://www.pagalguy.com/discussions/gmat-data-sufficiency-discussions-25020702
Yogesh, Ans for this one should be B ...
This question has already been posted some time back ..
Oh thanks,
sorry for posting the question again... will search the thread next time before posting...
Try this:
If two copying machines work simultaneously at their respective constant rates, how many copies do they produce in 5 minutes?
(1) One of the machines produces copies at the constant rate of 250 copies per minute.
(2) One of the machines produces copies at twice the constant rate of the other machine
try this
If x and y are positive, is x3 > y?
(1) sqrt x > y
(2) x > y
Try this:
If two copying machines work simultaneously at their respective constant rates, how many copies do they produce in 5 minutes?
(1) One of the machines produces copies at the constant rate of 250 copies per minute.
(2) One of the machines produces copies at twice the constant rate of the other machine
Individually neither of the statements is sufficient...
Together, we don't know which one produces twice as many copies...
IMO E..
try this
If x and y are positive, is x3 > y?
(1) sqrt x > y
(2) x > y
By each statement we can deduce that x > y, hence 3x>y..
IMO D..
Wats the OA?
could anybody please help me out with the logic of this DS problem? i guess, am missing out on something very simple. looking forward to hearing from you guys..if possible please post the funda. :-P
1) During an experiment, some water was removed from each of 6 tanks. If the standard deviation of the volumes of water in the tanks at the beginning of the experiment was 10 gallons, what was the std deviation of the volumes of water in the tanks at the end of the experiment?
(1) For each tank, 30% of the volume of water that was in the tank at the beginning of the experiment was removed during the experiment.
(2) The average(arithmetic mean) volume of water in the tanks at the end of the experiment was 63 gallons.
try this
If x and y are positive, is x3 > y?
(1) sqrt x > y
(2) x > y
By each statement we can deduce that x > y, hence 3x>y..
IMO D..
Wats the OA?
I believe the question is : is x^3>y ?
Then , Ans should be E ..
When we have positive range : we can think of 2 poss ranges :
a) 0
St 1 : think of +ve fraction below 1 and no above 1 ...not suff..
St 2 : all tells us nothing ..
Combined : when 0
So, if y is any value between x and x^3, y>x^3
And when x>1, x^3 >y ...not suff ..
Ans E
could anybody please help me out with the logic of this DS problem? i guess, am missing out on something very simple. looking forward to hearing from you guys..if possible please post the funda. :-P
1)During an experiment, some water was removed from each of 6 tanks. If the standard deviation of the volumes of water in the tanks at the beginning of the experiment was 10 gallons, what was the std deviation of the volumes of water in the tanks at the end of the experiment?
(1)For each tank, 30% of the volume of water that was in the tank at the beginning of the experiment was removed during the experiment.
(2)The average(arithmetic mean) volume of water in the tanks at the end of the experiment was 63 gallons.
Hello Puy ...this is a very good concept ...
Check out the funda and detailed discussion here ..(post 1225)
http://www.pagalguy.com/discussions/gmat-data-sufficiency-discussions-25020702
OA is A
Individually neither of the statements is sufficient...
Together, we don't know which one produces twice as many copies...
IMO E..
I agree...
I believe the question is : is x^3>y ?
Then , Ans should be C ..
When we have positive range : we can think of 2 poss ranges :
a) 0b) x>1
St 1 : think of +ve fraction below 1 and no above 1 ...not suff..
St 2 : all tells us nothing ..
Combined : x is above 1, hence x^3 is always greater than y ...suff
Folks,
Consider a situation: x=1/3, y=1/2
Here, sqrt(x)>y. But x
try this
If x and y are positive, is x3 > y?
(1) sqrt x > y
(2) x > y
Folks,
Consider a situation: x=1/3, y=1/2
Here, sqrt(x)>y. But x
U r assuming x to be a no greater than 1 ..
let it be a fraction between 0 and 1 ..
eg .1/2 > 1/3 but 1/8 is not greater than 1/3 ...St 2 is not suff ..
after combining also, not suff ..
ANs E
@bhavin422
Great point! My bad...
But then the answer should be "E".
Consider this: x=1/2, y=1/5
Here, x>y.
Also, x2>y (1/4>1/5)
But, x3
So we end up with an "E".
@deepakraam
Great question dude! Keep posting such stuff. This helps improve our skills by leaps and bounds...
Q. Atleast 100 students at a certain high school study Japanese. If 4% of the students at the school who study French also study Japanese, do more students at the school study French than Japanese?
1) 16 students at the school study both French and Japanese.
2) 10% of the students at the school who study Japanese also study French.
Please explain...
Q. Atleast 100 students at a certain high school study Japanese. If 4% of the students at the school who study French also study Japanese, do more students at the school study French than Japanese?
1) 16 students at the school study both French and Japanese.
2) 10% of the students at the school who study Japanese also study French.
Please explain...
Statement 1 is nt suff since we cannot exactly say huv many students are studying Japanese (atleast 100).
Statement 2 suff.since we get a % of Japanese studying students we can get the value of French studying students.
So I wud go with option B for the above one.
Statement 1 is nt suff since we cannot exactly say huv many students are studying Japanese (atleast 100).
Statement 2 suff.since we get a % of Japanese studying students we can get the value of French studying students.
So I wud go with option B for the above one.
deepakraam, good catch (atleast 100). I almost missed that boundary condition.
We cannot really highlight the importance paying sufficient attention to boundary conditions!
deepak, your answer is right.. OA is B.
Can you please solve it.. I still can't find out y B is sufficient??
Statement 1 is nt suff since we cannot exactly say huv many students are studying Japanese (atleast 100).
Statement 2 suff.since we get a % of Japanese studying students we can get the value of French studying students.
So I wud go with option B for the above one.