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The price per share of stock X increased by 10 percent over

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Manager
Joined: 28 Feb 2003
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The price per share of stock X increased by 10 percent over [#permalink]

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15 Sep 2003, 03:37
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The price per share of stock X increased by 10 percent over the same time period that the price per share of stock Y decreased by 10 percent. The reduced price per share of stock Y was what percent of the original price per share of stock X?

(1) The increased price per share of stock X was equal to the original price per share of stock Y
(2) The increase in the price per share of stock X was 10/11 the decrease in the price per share of stock Y
[Reveal] Spoiler: OA

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15 Sep 2003, 03:57
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If X is original proce of stock x and Y original price of stock y.
then we are asked to find : 0.9Y/X

1) 1.1X = Y => we can calculate above ratio, thus suffecient.
2) 0.1X=10/11*0.1Y => we can calculate above ratio, thus suffecient.

- Vicks
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08 Feb 2004, 09:41
I believe D is the answer.

Reduced price of Y is 0.9Y and original price of share X is X
so 0.9Y = k * X we need to determine K here.

A) 1.1X = Y
We have 0.9Y = K * X so K = 0.9Y/X = 0.9 * 1.1 X / X = 0.99
B) 0.1 X = 10/11 * 0.1 Y or X = 10Y/11
We have K = 0.9Y/X so K = 0.9Y * 11 / 10Y = 0.99
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08 Apr 2007, 12:15
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ggarr wrote:
The price per share of stock x increased by 10% over the same time period that the price per share of stock Y decreased by 10%. The reduced price per share of stock y was what percent of the original price per share of stock x?

(1) The increased price per share of stock x was equal to the original pricer per share of stock y?

(2) The increase in the price per share of stock x was 10/11 the decrease in the price per share of stock y.

X became 1.1 X and Y became 0.9 Y

we need to figure out 0.9Y/X = ?

From 1) we have 1.1x = y so Y/X = 1.1 hence SUFF
From 2) 0.1 X = 10/11 (0.1 Y) Again you can get X/Y so SUFF

what is the OA?
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Re: DS: stock price % increase (OG #111) [#permalink]

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10 Sep 2008, 01:29
D

droopy57 wrote:
The price per share of stock X increased by 10 percent over the same time period that the price per share of stock Y decreased by 10 percent. The reduced price per share of stock Y was what percent of the original price per share of stock X?

1) The increased price per share of stock X was equal to the originial price per share of stock Y

2) The increase in the price per share of stock X was 10/11 the decrease in the price per share of stock Y

D

1) 1.1x = y suff

2) .1x * 11/10 = .1y suff
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Re: The price per share of stock X [#permalink]

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28 Aug 2010, 11:28
2
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Expert's post
seekmba wrote:
The price per share of stock X increased by 10 percent over the same time period that the price per share of stock Y decreased by 10 percent. The reduced price per share of stock Y was what percent of the original price per share of stock X?

(1) The increased price per share of stock X was equal to the original price per share of stock Y.
(2) The increase in the price per share of stock X was 10/11 the decrease in the price per share of stock Y.

I got lost in the above options and did not understand how to solve each. Will appreciate if someone (may be Bunuel) can help solve (1) and (2).

Let the initial price per share of stock X be $$x$$, so after increase by 10% it would become $$1.1x$$;
Let the initial price per share of stock Y be $$y$$, so after decrease by 10% it would become $$0.9y$$.

Question: $$\frac{0.9y}{x}=\frac{9y}{10x}=?$$

(1) $$1.1x=y$$ --> $$\frac{9y}{10x}=\frac{9*1.1x}{10x}=0.99$$ or 99%. Sufficient.

(2) $$1.1x-x=\frac{10}{11}*(y-0.9y)$$ --> $$0.1x=\frac{10}{11}*0.1y$$ --> $$1.1x=y$$ the same info as in (1). Sufficient

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Re: The price per share of stock X [#permalink]

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28 Aug 2010, 12:31
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Thanks Bunuel.

I did not understand how you arrived at the below equation.

Question: $$0.9y/x = 9y/10x = ?$$

The reduced price per share of stock Y (0.9y) was what percent of the original price per share pf stock X (x). The reason I put $$?/100$$ is because we do not know the percentage and thats what we have to find out. What am I missing here??

--->$$0.9y = (x) X (?)/100$$
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Re: The price per share of stock X [#permalink]

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28 Aug 2010, 12:41
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Expert's post
seekmba wrote:
Thanks Bunuel.

I did not understand how you arrived at the below equation.

Question: $$0.9y/x = 9y/10x = ?$$

The reduced price per share of stock Y (0.9y) was what percent of the original price per share pf stock X (x). The reason I put $$?/100$$ is because we do not know the percentage and thats what we have to find out. What am I missing here??

--->$$0.9y = (x) X (?)/100$$

You got the same thing: $$0.9y=\frac{x*?}{100}$$ --> $$?=\frac{0.9y}{x}*100$$, where "?" represents the value we are looking for. The only difference is that you have it already transformed in percents and I have it as fraction.

Generally if we are asked $$m$$ is what percent of $$n$$ then: $$%=\frac{m}{n}*100$$.
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Re: The price per share of stock X [#permalink]

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28 Aug 2010, 14:15
Ok so i was on right track. Thanks a bunch aagain
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Re: OG 11 DS #111 [#permalink]

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14 Apr 2011, 10:30
3
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tonebeeze wrote:
I got the problem correct. I just want to make sure my algebra translations are on point. Can someone please walk me through the algebra? Thanks!

The price per share of stock X increased by 10 percent over the same time period that the price per share of stock Y decreased by 10 percent. The reduced price per share of stock Y was what percent of the original price per share of stock X?

1. The increased price per share of stock X was equal to the original price per share of stock Y.

2. The increase in the price per share of stock X was 10/11 the decrease in the price per share of stock Y.

 Stocks Data Stock Name Price/Share(2005) Increase/Decrease in Price Reduced/Increased Price/Share(2010) X x 0.1x Increase 1.1x (Increased Price) Y y 0.1y Decrease 0.9y(Reduced Price)

Table above shows the price of stock X and Y in 2005 and 2010(duration of time for the change is same). Rest of the fields are self-explanatory.

Q: The reduced price per share of stock Y was what percent of the original price per share of stock X?

$$0.9y=(\frac{WHAT}{100})*x$$
$$WHAT=(\frac{0.9*100y}{x})$$
$$WHAT=(\frac{90y}{x})$$

Rephrase:
Q: What is $$\frac{y}{x}$$?

1. The increased price per share of stock X was equal to the original price per share of stock Y.
$$1.1x=y$$
$$\frac{y}{x}=1.1$$
Sufficient.

2. The increase in the price per share of stock X was 10/11 the decrease in the price per share of stock Y.

$$0.1x=\frac{10}{11}*0.1y$$
$$\frac{y}{x}=\frac{11}{10}$$
$$\frac{y}{x}=1.1$$
Sufficient.

Ans: "D"
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Re: OG 11 DS #111 [#permalink]

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14 Apr 2011, 19:26
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X2 = 1.1X

Y2 = 0.9Y

So Y2/X = ?

(1) -> X2 = Y

=> 1.1X = Y2/0.9

=> Y2/X = 99/100

sufficient

(2) -> X2 - X = 10/11(Y - Y2)

=> 1.1X - X = 10/11(0.1Y)

=> 0.1X = 0.1Y * 10/11

=> X = Y * 10/11

=> X = 10Y2 / 9 * 10/11

=> Y2/X = 99/100

Sufficient

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Re: Percents - "Stock Comparison" Question [#permalink]

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15 Aug 2011, 22:12
restore wrote:
The price per share of Stock X increased by 10 percent over the same time period that the price per share of Stock Y decreased by 10 percent. The reduced price per share of Stock Y was what percent of the original price per share of Stock X?

1. The increased price per share of Stock X was equal to the original price per share of Stock Y.
2. The increase in price per share of Stock X was $$10/11$$ the decrease in the price per share of Stock Y.

x1 = original price of x
x2 = new price of x
x2 = 1.10 x1

y1 = original price of y
y2 = new price of y
y2 = (0.90)y1

Question: reduced price of y (y2) / increased price of x (x1) = ?

Statement 1: The increased price per share of Stock X was equal to the original price per share of Stock Y.
x2 = y1
(1.10) x1 = y2/(0.90)
(1.10) (0.90) x1 = y2
y2/x1 = (1.10) (0.90)
y2/x1 = 0.99 ---------Sufficient....

Statement 2: The increase in price per share of Stock X was $$10/11$$ the decrease in the price per share of Stock Y.

x2-x1 = 10/11 (y1-y2)
11 (x2-x1) = 10 (y1-y2)
11 [(1.10) x1 - x1)] = 10 [(y2/0.90) -y2]
(0.11) x1 = [(y2 -0.9y2)/0.90]
(0.11) (0.90) x1 = (0.1) y2
(0.099) x1 = (0.1)y2
(0.99) x1 = y2
y2/x1 = 0.99 ---------Sufficient....

D.
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Re: Percents - "Stock Comparison" Question [#permalink]

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16 Aug 2011, 03:09
1
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Suppose original price of Stock X and Stock Y is 100 and 110 respectively
New price of Stock X= 110
New price of Stock Y = 99

Stmt1: The increased price per share of Stock X was equal to the original price per share of Stock Y.
110=110.
The reduced price per share of Stock Y was what percent of the original price per share of Stock X?
=99/100*100 =99
Sufficient.

Stmt2: The increase in price per share of Stock X was 10/11 the decrease in the price per share of Stock Y.
10=10/11 (11)
The reduced price per share of Stock Y was what percent of the original price per share of Stock X?
=99/100*100 =99
Sufficient.

OA D
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Re: The price per share of stock X increased by 10 percent over [#permalink]

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10 Nov 2011, 12:00
1
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Just thought of posting another way to solve this.

Since the final value to find is a percent -
Assume original value of x is 100. New value of x is 110
Original value of y is y. New value is 0.9y
What is (.9y/100) 100 =?
(1) 110 = y
Sufficient
(2) 10 = 10/11 (0.1y)
Sufficient

Ans: D

Note that (1) and (2) give the same data in different forms.
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Re: The price per share of stock X increased by 10 percent over [#permalink]

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22 Aug 2013, 01:58
Sorry All but I was not able to view the options given. I am using Firefox browser.
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Re: The price per share of stock X increased by 10 percent over [#permalink]

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22 Aug 2013, 02:30
SrirFwd wrote:
Sorry All but I was not able to view the options given. I am using Firefox browser.

This is a data sufficiency question. Options for DS questions are always the same.

The data sufficiency problem consists of a question and two statements, labeled (1) and (2), in which certain data are given. You have to decide whether the data given in the statements are sufficient for answering the question. Using the data given in the statements, plus your knowledge of mathematics and everyday facts (such as the number of days in July or the meaning of the word counterclockwise), you must indicate whether—

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 asked, but NEITHER statement ALONE is sufficient to answer the question asked.
E. Statements (1) and (2) TOGETHER are NOT sufficient to answer the question asked, and additional data specific to the problem are needed.

Hope this helps.
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Re: The price per share of stock X increased by 10 percent over [#permalink]

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25 Nov 2015, 17:42
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Given
1.1x
0.9y

(0.9y/x)*100 = ¿?
THE KEY: This is a COMBO QUESTION --> Knowing y/x (or knowing that you have sufficient information to know y/x) is sufficient.

Statement 1
1.1x = y
If you manipulate the equation, you can get y/x

Statement 2
0.1x = (10/11) 0.1y
If you manipulate the equation, you can get y/x

Note the difference between:
- the increase IN THE price of x -->0.1x
- the decrease IN THE price of y --> 0.1y
- the INCREASED price in x --> 1.1x
- the DECREASED price in y -->0.9y
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Re: The price per share of stock X increased by 10 percent over [#permalink]

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24 May 2016, 22:59
Bunuel, really nice explanation. Thanks a lot!
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Re: The price per share of stock X increased by 10 percent over [#permalink]

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