GMAT Data Sufficiency Discussions

Hi,
Here are a few DS questions I couldn't solve,

q1. A company enlisted P people to sell 200 knives each, and each salesperson then enlisted P more people to sell 200 knives each. If eveyone sold their 200 knives, what is the value of P?
1) the first P people sold 1/9 of all the knives sold?
2) 14,400 knives were sold in total.
q2. A group of theater owners made an arrangement with an acting company stating that the theater owners would get $5 for every ticket sold. How much did the theater owner earn from the ticket sales?
1) The total revenue was $700
2) If 30 more tickets had been sold, the theater owners would have recvd 30% more money from ticket sales.
q3. Set S consists of n numbers arranged in asc. order. A new set is created as follows: each element in S is increased by a value = that number's place in S. By how much does the mean of the new set > the mean of the original set?
1) set S has 10 elements
2) The sum of elements in the original set is 100.
q4. 3 segments are drawn from opposite corners of a hexagon to form 6 triangles. These segments all bisect each other at pt A. Are the triangles equilateral?
1) All 6 sides are the same length.
2) The 3 segments drawn between the opposite corners are the same length.

Can somebody please help me solve them?




Thanks,
Shipra

q.2:
answer is B acc. to me....
st.1:
u cannot answer using this st.
st.2:
if they hd sold x tickets, the owners wud hv got $5x ...if they hd sold (x+30) tickets, the owners wud hv got $(5x+150) which is 30% more than 5x...
thus, u can find value of x and find out the answer..

q1. A company enlisted P people to sell 200 knives each, and each salesperson then enlisted P more people to sell 200 knives each. If eveyone sold their 200 knives, what is the value of P?
1) the first P people sold 1/9 of all the knives sold?
2) 14,400 knives were sold in total.



The first P people sold 200 knives each. Hence there were totally 200P knives with them. Each of these P then hired another P to sell 200 each. Hence we now have 200 * P * P.

Hence we have 200P^2 + 200P = x.

Now we need a value for x to solve this equation. Choice 2 gives us this information directly. Hence, the choices are down to B or D. Choice 1, while not giving us the total number of knives directly, tells us that

200 P = x/9. Hence x = 1800P. Substituting this value in the above equation will also help us solve it.

Hence the answer is D.

Vikram.

q3. Set S consists of n numbers arranged in asc. order. A new set is created as follows: each element in S is increased by a value = that number's place in S. By how much does the mean of the new set > the mean of the original set?
1) set S has 10 elements
2) The sum of elements in the original set is 100.



I think the answer is A.

Reason: The increase in the new set is always a constant. Let that constant be C.

Now, if the sum of terms in the original set is x and the number of terms is n, then the mean is x/n.

Now upon increase the mean would be (x+C)/n.

Hence the increase would be ((x+c)/n) - (x/n) = C/n. To get this number we will need the number of elements n (using which C can be determined, too). Hence Choice 1 suffices.

For choice 2, while it is said that the numbers are arranged in ascending order, we are not given any information about what numbers these are. Hence the sum of the numbers doesnt give us any information to determine n.

Vikram.

Hi Guys,



Here's another question I got wrong in one of the tests...



Q18. Is the measure of one of the interior angles of quadrilateral ABCD equal to 60 degrees?

1)2 of the interior angles of ABCD are right angles
2)The degree measure of angle ABC is twice that of angle BCD

I'll post the correct answer shortly...

thanks,
shipra

Hi Guys,



Here's another question I got wrong in one of the tests...



Q18. Is the measure of one of the interior angles of quadrilateral ABCD equal to 60 degrees?

1)2 of the interior angles of ABCD are right angles
2)The degree measure of angle ABC is twice that of angle BCD

I'll post the correct answer shortly...

thanks,
shipra

i guess the answer is E....
using st.1, we knw that the sum of other two angles = 180 deg. so possible combinations can be 60,120 or 50,130 etc..
using st.2, we do not knw the exact measure cuz the quadrilateral can have angles as 50,100,200,10 or 60,120,40,140 etc..
using both st. together,
if we consider angle ABC = 90 deg (one of the right angles), then other angle will be 45 deg..so the angles of quad can be 90,90,45,135
or, the other solution set can be 60,120,90,90...so u dont hv a unique answer on tht too...
Hi Guys,



Here's another question I got wrong in one of the tests...



Q18. Is the measure of one of the interior angles of quadrilateral ABCD equal to 60 degrees?

1)2 of the interior angles of ABCD are right angles
2)The degree measure of angle ABC is twice that of angle BCD

I'll post the correct answer shortly...

thanks,
shipra


Is there a figure that goes along with this question???? The answer would depend on how the figure looks. If there is no figure, then the answer is E. But if there is a figure, then the answer could be different!

Vikram.
Is there a figure that goes along with this question???? The answer would depend on how the figure looks. If there is no figure, then the answer is E. But if there is a figure, then the answer could be different!

Vikram.

as far as i know, there is no figure tht has accompanied this question..

Is the answer 'b' correct for the above problem ?

If y is greater than 110 percent of x,is y greater than 75
1.x>75
2.y-x=10

If y is greater than 110 percent of x,is y greater than 75
1.x>75
2.y-x=10

since y is greater than 110% of x,

y>1.1x

using st.1 alone,
let x = 76
obviously, in all cases, y>1.1x
hence, st.1 alone is sufficient

using st.2 alone,
x = y-10
hence,
y>1.1(y-10)
y>1.1y-11
.1yyso y can be 80 or y can also be 10
st.2 alone is not sufficient.

hence, answer is A.

@ajay
thanx

If y is greater than 110 percent of x,is y greater than 75
1.x>75
2.y-x=10


given y>1.1x.

taking condition 1) x>75 will always give y>1.1 *75. hence y>75

now take condition 2) y-x=10=>x=y-10.
y>1.1(y-10)=>y>1.1y -11=>0.1yyhence we can't say if y>75
so only statement 1) gives the answer

Hi All,

A couple of questions encoutered in practice tests:

1. Is 1/p > r/(r*r + 2)

a. p=r
b. r > 0


-----------------------

2. If m and n are integers, is m odd.

a. n+m is odd
b. n+m = n*n + 5

----------------------------------------

3. If y > = 0, what is the value of x.

a. x - 3| > = y
b. |x - 3 =
I have the answers, but need help with reasoning.
Hence please post the approach and reasoning as well.

Thanks in advance.

hi radhika
for the first two DS ques
1. both the statements are req.
2. only b is sufficient
do tell the ans, if correct i ll post the soln.
regards
rock
hi radhika
for the first two DS ques
1. both the statements are req.
2. only b is sufficient
do tell the ans, if correct i ll post the soln.
regards
rock



Both are correct.

2. If m and n are integers, is m odd.

a. n+m is odd
b. n+m = n*n + 5

B is sufficient

if n is odd, then n*n is odd and n*n+5 is even. Thus only an odd number (m) when added to n will produce an even number
if n is even, then n*n is even and n*n+5 is odd. Thus only an odd number (m) when added to n will produce an odd number

n+m is odd - is leaving the options open because one of them could be odd and still meet the condition


3. If y > = 0, what is the value of x.

a. x - 3| > = y
b. |x - 3 =
I believe again b will be sufficient to answer the question (though i am not sure) because the only condition that will satisfy the condition b is abs(x-3)=0 otherwise x = 3 ... i will wait for other readers to reply to that question

thanks

1. Is 1/p > r/(r*r + 2)
1. p=r
2. r > 0
from stat.1 we have a number of options
as p and q can be positive, negative as well as fractions
so nuthing cn be definite
now using stat.2 alone which specifies r>0
we surely cant reach any conclusion
but definitly using both 1& 2
we reach a common ans regardless
of the fact if dey r in decimal form or integers.
2. If m and n are integers, is m odd.
1. n+m is odd
2. n+m = n*n + 5
here using stat. 1 we cnt concluted about m as it cn be both
even or odd depending upon n
now, we move on to stat.2
we cn rearrange the condition as
n^2-n+(5-m)=0
simply try n substitute once and even value and den an odd value for n
i.e
if n=2 den m=7
if n=3 den m= 11
observing the pattern for a few mr nos
we cn definetly say for either n being even or odd
m has to be odd
hope it helps
regards
rock
Hi All,

A couple of questions encoutered in practice tests:

1. Is 1/p > r/(r*r + 2)

a. p=r
b. r > 0


-----------------------

2. If m and n are integers, is m odd.

a. n+m is odd
b. n+m = n*n + 5

----------------------------------------

3. If y > = 0, what is the value of x.

a. x - 3| > = y
b. x - 3 =
I have the answers, but need help with reasoning.
Hence please post the approach and reasoning as well.

Thanks in advance.


1) 1/p>r/(r*r +2)
=>r*r +2>pr
=>r*r -pr +2>0 -----eqn
condition a)if p=r then
eqn => 2>0.
hence condition a) is sufficient to answer the question

2)
a) m+n =odd, hence either m=odd and n=even or else m=even and n=odd
d)n+m=n*n +5
=>n*n -n=m-5
=>n(n-1)=m-5
consider n=even then n-1=odd, so n(n-1)=even. assuming m=odd,if m=7,9... etc then m-5=even
hence both the condition are required.

3)given y>=0
a)x - 3 > = y
=>x - 3 > =0
=>x-3>=0
=>x>=3
b)x - 3 = =>|x - 3 ==>-x +3==>x>=3
hence anyone of the condition will give the range but not accurate value
2. If m and n are integers, is m odd.

a. n+m is odd
b. n+m = n*n + 5

B is sufficient

if n is odd, then n*n is odd and n*n+5 is even. Thus only an odd number (m) when added to n will produce an even number
if n is even, then n*n is even and n*n+5 is odd. Thus only an odd number (m) when added to n will produce an odd number

n+m is odd - is leaving the options open because one of them could be odd and still meet the condition


3. If y > = 0, what is the value of x.

a. x - 3| > = y
b. |x - 3 =
I believe again b will be sufficient to answer the question (though i am not sure) because the only condition that will satisfy the condition b is abs(x-3)=0 otherwise x = 3 ... i will wait for other readers to reply to that question

thanks


Yes. You are right with both answers. thanks for the explanation.

Is u>v ?
1) u^2=v^2
2) u,v>0
A) Statement 1 alone is sufficient but statement 2 alone is not sufficient to answer the question asked.
B) Statement 2 alone is sufficient but statement 1 alone is not sufficient to answer the question asked.
C) Both statements 1 and 2 together are sufficient to answer the question but neither statement is sufficient alone.
D) Each statement alone is sufficient to answer the question.
E) Statements 1 and 2 are not sufficient to answer the question asked and additional data is needed to answer the statements.

i think answer cant be determined 😐