GMAT Problem Solving Discussions

MBA
1123

I think the Answer to this question as it is - is (B).

But it seems to be mistyped - shouldn't the equation be 2x+3y 6 or something like that?

How can a "region" refer to a "line" ?!

If that's the case, then the Answer would differ.

Need help with the following data sufficiency problem. Plz provide explanation.

Q. In a xy plane, region R consists of all the points (x,y) such that 2x+3y=6. Is the point (r,s) in region R?

1. 3r+2s=6
2. r=3 and s=2

Rgds
MSD
1124
Need help with the following data sufficiency problem. Plz provide explanation.

Q. In a xy plane, region R consists of all the points (x,y) such that 2x+3y=6. Is the point (r,s) in region R?

1. 3r+2s=6
2. r=3 and s=2

Rgds
MSD

Answer is B only from that we can deduec that it is not lying in the above mentioned region
do u have the key
1125

Hi all,

i am stuck with such a basic question... need ur help..

its 11^2+ 12^2+...........+20^2

i know we have to use the formmula n(n+1)(2n+1)/6 but whats 'n' here..

i read the explanation somewhere saying first we need to calculate sum of the square of 1 to 20 ( 1^2+ 2^2....20^2) and subratct from it (1^2+2^2....10^2)... but the its takes lot of time .and will be tiresome for bigger numbers,,

is there any other way 2 solve this ,,

thanks

Sudhir

1126

Pls help with reasoning.......OA's are given.......

1127
ashishjha100 Says
Pls help with reasoning.......OA's are given.......


Explanation for first one

1.If the sum of two integers is 6, then it must be true that
(A) both integers are even
(B) both integers are odd
(C) both integers are positive
(D) if one integer is negative, the other is positive
(E) if one integer is positive, the other is negative
(A)-we can have 3,3 or 1,5 -Not true
(B) 2,4- -not true
(c) 7,-1 or 8,-2 .... - not true
(D) if one is -ve then other has to be positive -So it must be true
(E) If one is positive then other can be -ve ot +V depending on the Number

So only statement D is always true
1128
1. Five pieces of wood have an average (AM)length of 124 cm and a median length of 140 cm. What is the maximum possible length,in cm,of the shortest piece of wood?

a) 90 b) 100 c) 110 d) 130 e) 140

2. For any +ve integer n is defined as the number of prime factors whose product is n. For example, the length of 75 is 3, since 75=3*5*5. How many two-digit +ve intergers have length 6?

a) None b)One c)Two d)three e) Four

Pls post ur answers with explanation...i will post the answers..tomorrow..


My Attempt1) Median is 140 so last three will be atleast 140 (Sum of deviation from mean = 140-124 x 3 = 16x3 = 4 (If we will increase the value of the 3 largest, value of least will decrease).Sum of the rest of the two will be 124*2-48 = 200So maximum value for the lest will be 200/2 = 100 (max possible is that the two are equal) Concept used here is that the sum of deviation of each element of the set from its Mean is zero. So Choice B2) We have to find the combination of 6 prime nos out of 2,3,5,7,11 ......... 2*2*2*2*2*2=642*2*2*2*2*3=962*2*2*2*3*3=114 Any other combination will result in more than 100 So choice C
1129
Answer is B only from that we can deduec that it is not lying in the above mentioned region
do u have the key

The OA is E. Can you explain how that can be the answer?
1130
1. Five pieces of wood have an average (AM)length of 124 cm and a median length of 140 cm. What is the maximum possible length,in cm,of the shortest piece of wood?

a) 90 b) 100 c) 110 d) 130 e) 140

2. For any +ve integer n is defined as the number of prime factors whose product is n. For example, the length of 75 is 3, since 75=3*5*5. How many two-digit +ve intergers have length 6?

a) None b)One c)Two d)three e) Four

Pls post ur answers with explanation...i will post the answers..tomorrow..


My ans are
1. e
2. c
1131

OA's are 1)100 and 2)Two....

abhishekag05 Says
My Attempt1) Median is 140 so last three will be atleast 140 (Sum of deviation from mean = 140-124 x 3 = 16x3 = 4 (If we will increase the value of the 3 largest, value of least will decrease).Sum of the rest of the two will be 124*2-48 = 200So maximum value for the lest will be 200/2 = 100 (max possible is that the two are equal) Concept used here is that the sum of deviation of each element of the set from its Mean is zero. So Choice B2) We have to find the combination of 6 prime nos out of 2,3,5,7,11 ......... 2*2*2*2*2*2=642*2*2*2*2*3=962*2*2*2*3*3=114 Any other combination will result in more than 100 So choice C
1132

Thank u for answers...OA's are 100 & Two...Can u pls give explanations?

My take is

Q1 - Answer (b) = 100

Q2 - Answer (c) = Two

what are the OAs?
1133

Hi OA's ..1)100 2)TWO...

Pls re chk ur answer for first one...can u pls give explanation for 2nd q?

My ans are
1. e
2. c
1134

1. Five pieces of wood have an average (AM)length of 124 cm and a median length of 140 cm. What is the maximum possible length,in cm,of the shortest piece of wood?

Let's assume the pieces of wood are a,b,c,d & e. (in increasing order of length);
(a+b+c+d+e)/5 = 124; therefore a+b+c+d+e = 620
Median length is 140 --> c = 140; therefore a+b+d+e = 620-140 = 480.

Now we know that if c=140, a&b;
we must assume the minimum length for the largest piece, in order to obtain the maximum possible length of the shortest piece. Also assume a=b and d=e (the two shortest pieces and longest pieces are of the same length)

The minimum length of the largest piece is 140. Substituting this in the equation;
a+b + 140 +140 = 480;
2(a) = 480 - 280
a = 200 /2 = 100 (max. length of the shortest piece).

-----------------------------------------------------------------
2. For any +ve integer n is defined as the number of prime factors whose product is n. For example, the length of 75 is 3, since 75=3*5*5. How many two-digit +ve intergers have length 6?

We need to find two-digit +ve integers which have 6 prime factors.

64 = 2*2*2*2*2*2
96 = 2*2*2*2*2*3

64, 96 are the only two-digit numbers which have a length of 6. (Try substituting more "2"s with "3"s in the above numbers, they won't remain 2-digit anymore)

Bunty4Billi Says
Thank u for answers...OA's are 100 & Two...Can u pls give explanations?
1135
Last year the price per share of Stock X increased by k percent and the earnings per share
of Stock X increased by m percent, where k is greater than m. By what percent did the
ratio of price per share to earnings per share increase, in terms of k and m?
A. k m %
B. (k - m) %
C. / (100 + k) %
D. / (100 + m) %
E. / (100 + k + m) %
1136

I think the Answer is (D).

What is the OA?

Last year the price per share of Stock
X increased by k percent and the earnings per share
of Stock X increased by m percent, where k is greater than m. By what percent did the
ratio of price per share to earnings per share increase, in terms of k and m?
A. k m %
B. (k m) %
C. / (100 + k) %
D. / (100 + m) %
E. / (100 + k + m) %

1137
I think the Answer is (D).

What is the OA?

OA is D ...........pls provide explanation.....
1138

p -> price per share; After k% increase -> (kp/100) + p
e -> earnings per share; After m% increase -> (me/100) + e

ratio of original price per share to earnings per share is p/e

ratio of new price per share to new earnings per share is
/

the percentage increase will be (diff between the two ratios)/(original ratio) x 100

solve to get 100(k-m) / 100+m (Note:- e and p will cancel during the calculation)

ashishjha100 Says
OA is D ...........pls provide explanation.....
1139
p -> price per share; After k% increase -> (kp/100) + p
e -> earnings per share; After m% increase -> (me/100) + e

ratio of original price per share to earnings per share is p/e

ratio of new price per share to new earnings per share is
/

the percentage increase will be (diff between the two ratios)/(original ratio) x 100

solve to get 100(k-m) / 100+m (Note:- e and p will cancel during the calculation)


Hey Arch,

I did try calculating the answer as per your method.....however, I am getting e^2(k-m)*100 as the answer. I donno where I am going wrong. Would you mind posting the steps involved in calculation?

Thanks
MSD
1140

original ratio = p/e
new ratio = / = /

difference between original ratio and new ratio is given by

- (p/e)
= / e*
= /e*
= / --> cancel "e" from numerator and denominator
= p* /

Percentage increase is obtained by (diff between ratio)/(original ratio)*100

--> / (p/e) * 100 %
--> p and e cancel
--> 100* (k-m) / (m+100) %

Hope this helps!

Hey Arch,

I did try calculating the answer as per your method.....however, I am getting e^2(k-m)*100 as the answer. I donno where I am going wrong. Would you mind posting the steps involved in calculation?

Thanks
MSD
1141
ashishjha100 Says
Pls help with reasoning.......OA's are given.......


Perimeter of the rectangle is 18/ squareroot 2
L+B = 9 / squareroot 2
In terms of breadth of the rectangle
2(side of square)^2 = B^2; (Side of square)^2 = B^2/ 2
In terms of length of the rectangle
2(side of square)^2 = L^2/ 4; (side of square)^2 = L^2/ 8
Thus we can say that L^2/ 8 = B^2/ 2.....this means L/2 = B
Hence, L+L/2 = 9/ squareroot 2; L = 3* squareroot 2
(Side of square)^2 = (3* squareroot 2)^2 / 8
Side of square = 3/2
Therefore perimeter of 2 squares = 3/2 * 8 = 12
Answer is B

Rgds
MSD
1142
ashishjha100 Says
Pls help with reasoning.......OA's are given.......


Question 4
Perimeter of the rectangle is 18/ squareroot 2
L+B = 9 / squareroot 2
In terms of breadth of the rectangle
2(side of square)^2 = B^2; (Side of square)^2 = B^2/ 2
In terms of length of the rectangle
2(side of square)^2 = L^2/ 4; (side of square)^2 = L^2/ 8
Thus we can say that L^2/ 8 = B^2/ 2.....this means L/2 = B
Hence, L+L/2 = 9/ squareroot 2; L = 3* squareroot 2
(Side of square)^2 = (3* squareroot 2)^2 / 8
Side of square = 3/2
Therefore perimeter of 2 squares = 3/2 * 8 = 12
Answer is B

Rgds
MSD