How many shares of company X stock

[rsarashi]

Of the shares of stock owned by certain investor, 30 percent are share of company X stock and 1/7 of the remaining shares are shares of company Y stock. How many shares of company X stock does the investor own?

|) The investors owns 100 shares of company Y stock.

||) The investor owns 200 more shares of company X stock than of company Y stock.

OAD

[GMATGuruNY]

Of the shares of stock owned by a certain investor, 30 percent are shares of Company X stock and 1/7 of the remaining shares are shares of Company Y stock. How many shares of Company X stock does the investor own?

(1) The investor owns 100 shares of Company Y stock.
(2) The investor owns 200 more shares of Company X stock than of Company Y stock.

To determine the ratio of X and Y, plug in a value for the total number of shares.

Since the problem features two fractions -- 30% = 3/10 and 1/7 -- the total number of shares should be a value divisible by both 10 and 7.
Let the total number of shares = 70.
Since 30% of the shares are of Stock X, X = (3/10)(70) = 21.
Remaning shares = 70-21 = 49.
Since 1/7 of the remaining shares are of Stock Y, Y = (1/7)(49) = 7.
Thus:
X:Y = 21:7 = 3:1.

Statement 1: The investor owns 100 shares of Company Y stock
Since X:Y = 3:1 = 300:100, X=300 and Y=100.
SUFFICIENT.

Statement 2: The investor owns 200 more shares of Company X stock than of Company Y stock
Statement 2 implies the same values as Statement 1:
X=300 and Y=100, with the result that X-Y = 300-100 = 200.
SUFFICIENT.

The correct answer is D.

[Jay@ManhattanReview]

Of the shares of stock owned by certain investor, 30 percent are share of company X stock and 1/7 of the remaining shares are shares of company Y stock. How many shares of company X stock does the investor own?

|) The investors owns 100 shares of company Y stock.

||) The investor owns 200 more shares of company X stock than of company Y stock.

OAD

Hi rsarashi,

Percentage of stocks of Company X = 30%, thus the percentage of stocks of other companies = 100 - 30% = 70%.

Thus, the percentage of stocks of Company Y = 1/7 of 70% = 10%

=> Number of stocks of Company X = 3*Number of stocks of Company Y

Statement 1: The investors owns 100 shares of company Y stock.

Since we know that the number of stocks of Company X = 3*Number of stocks of Company Y, thus,

Number of stocks of Company X = 3*100 = 300. Sufficient.

Statement 2: The investor owns 200 more shares of company X stock than of company Y stock.

Say the number of stocks of Company Y = y, thus, the number of stocks of Company X = 200 + y

Since we know that the number of stocks of Company X = 3*Number of stocks of Company Y, thus,

200 + y = 3*y

y = 100 => x = 300. Sufficient.

The correct answer: D

Hope this helps!

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[Brent@GMATPrepNow]

Of the shares of stock owned by certain investor, 30 percent are share of company X stock and 1/7 of the remaining shares are shares of company Y stock. How many shares of company X stock does the investor own?

|) The investors owns 100 shares of company Y stock.

||) The investor owns 200 more shares of company X stock than of company Y stock.

OAD

Target question: What is the value of n?

Given - part a: Of the shares of stock owned by a certain investor, 30 percent are shares of Company X stock ..
If 30% of the shares are Company X, then 70% of the shares are NOT in Company X

Given - part b: ... and 1/7 of the remaining shares are shares of Company Y stock
1/7 of 70% = 10%, so 10% of the shares are in Company Y

Statement 1: The investor owns 100 shares of Company Y stock.
If 30% of the shares are Company X and 10% of the shares are in Company Y, then there are 3 TIMES as many shares in Company X as in Company Y.
(3)(100) = 300, so there are 300 shares in Company X.
Since we can answer the target question with certainty, statement 1 is SUFFICIENT

Statement 2: The investor owns 200 more shares of Company X stock than of Company Y stock.
So, (# of Company X shares) - (# of Company Y shares) = 200
Let T = total number of shares
So, (30% of T) - (10% of T) = 200
Rewrite as 0.3T - 0.1T = 200
Simplify: 0.2T = 200
Solve: T = 1000
So, there are 1000 shares altogether.
30% of the shares are in Company X, and 30% of 1000 = 300
So there are 300 shares in Company X.
Since we can answer the target question with certainty, statement 2 is SUFFICIENT

Answer = D

Cheers,
Brent

[[email protected]]

Hi rsarashi,

This DS question is essentially just a wordy algebra question. Properly translating the language in the main prompt into "math" will make the rest of the work really easy to do.

We're told that an investor owns some shares of stock, 30% of those total shares are of Stock X and 1/7 or the REMAINING shares are of Stock Y. Before doing anything else, I'm going to translate all of this into algebra:

T = Total shares owned
.3T = number of shares of Stock X

Now, to figure out the number of shares of Stock Y, we need to take the REMAINING shares (in this case, .7T shares) and multiply by 1/7...
.7T(1/7) = (7/10)(T)(1/7) = T/10 = .1T

.1T = number of shares of Stock Y

The question asks for the number of shares of Stock X, so it's asking for the value of .3T (in other words, if you can figure out the value of T, then you can answer the question).

Fact 1: The investor owns 100 shares of Stock Y

This means that .1T = 100.
We CAN solve for T and there is just one answer (and we can save time since we don't have to do the work to see that there's just one answer).
Fact 1 is SUFFICIENT

Fact 2: The investor owns 200 MORE shares of Stock X than Stock Y.

We can translate this into an equation:

.3T = .1T + 200
.2T = 200

Again, we CAN solve for T and there is just one answer.
Fact 2 is SUFFICIENT

Final Answer: D

GMAT assassins aren't born, they're made,
Rich

[Scott@TargetTestPrep]

Of the shares of stock owned by certain investor, 30 percent are share of company X stock and 1/7 of the remaining shares are shares of company Y stock. How many shares of company X stock does the investor own?

|) The investors owns 100 shares of company Y stock.

||) The investor owns 200 more shares of company X stock than of company Y stock.

OAD

We can let n = the total number of shares, x = the number of company X shares, and y = the number of company Y shares, and we can create the following equations:

0.3n = x

and

(1/7)(0.7)n = y

(1/7)(7/10)n = y

(1/10)n = y

If we can produce a third unique equation with one or more of the variables n, x, or y, or if we know one of the two values of n and y, we can determine the value of x.

Statement One Alone:

The investors owns 100 shares of company Y stock.

Since y = 100, we see that we can determine x. Statement one alone is sufficient to answer the question.

Statement Two Alone:

The investor owns 200 more shares of company X stock than of company Y stock.

We have:

y = 200 + x

Since we have a third unique equation, statement two alone is sufficient to answer the question.

If this is not obvious to you, here is an alternate explanation: In the equation y = 200 + x, we can substitute 0.3n for x and we can substitute 0.10n for y, yielding:

0.10n = 200 + 0.3n

At this point, we see that we can easily solve for n, and then for x.

Answer: D