BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

OG#177

Expert replies
by tapanmittal » Fri Jul 03, 2015 9:50 pm
Last year the price per share of stock X increased by k% and the earnings per share of stock X increased by m%,where>m.
By what percent did the ratio of price per share to earnings per share increase,in terms of k and m?

Ans-100(k-m)%/100+m

Searching for a shortest solution to approach such problems.
Join the discussion
Source: — Problem Solving |

by theCEO » Sat Jul 04, 2015 9:31 am
tapanmittal wrote:Last year the price per share of stock X increased by k% and the earnings per share of stock X increased by m%,where>m.
By what percent did the ratio of price per share to earnings per share increase,in terms of k and m?

Ans-100(k-m)%/100+m

Searching for a shortest solution to approach such problems.
Shortest way is to substitute values for all the unknowns.

original price/per share = 10
original earnings/per share = 10

k = 10 and m = 5
new price/per share = 10 + 10%(10) = 11
new earnings/per share = 10 + 5%(10)=10.5

Original ratio = 10/10 = 1
new ratio = 11/10.5

% increase = 100*(new ratio - old ratio)/ old ratio
% increase = 100*(11/10.5 -1)/10.5
% increase = 100*(11/10.5 - 10.5/10.5)/10.5
% increase = 100*(0.5)/10.5 = 50/10.5

Substitute k = 10 and m = 5 into the answer choices and see which answer gives 50/10.5
100(k-m)%/100+m
100(10-5)/100+5
500/105

500/105 = 50/10.5
Join the discussion

by [email protected] » Sat Jul 04, 2015 9:52 am
Hi tapanmittal,

When posting questions, you should include the 5 answer choices. In many prompts, the answers provide 'clues' as to how you might choose to approach the prompt. Since most GMAT questions can be approached in a variety of ways, knowing more than just the 'math approach' will help you to attack prompts in the fastest/easiest fashion and avoid the types of pacing issues that impact many Test Takers.

GMAT assassins aren't born, they're made,
Rich
Contact Rich at [email protected]
Image
Join the discussion

by nikhilgmat31 » Thu Jul 09, 2015 2:20 am
Well plugging values may be wrong by any minor mistake.

P (1+k/100)P
E (1+m/100)E

new ratio = (100+k)P/(100+m)E

old ratio = P/E

keep P/E as A

% change = ((100+K)A/100+m) - A ) /A *100

Cancelling A as common

(100+k -100-m )*100/(100 +m)

(k-m)100/(100+m)

Done
Join the discussion

by Scott@TargetTestPrep » Fri Jul 10, 2015 4:15 am
tapanmittal wrote:Last year the price per share of stock X increased by k% and the earnings per share of stock X increased by m%,where>m.
By what percent did the ratio of price per share to earnings per share increase,in terms of k and m?

Ans-100(k-m)%/100+m

Searching for a shortest solution to approach such problems.

177) 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 - m)] / (100 + k) %
D. [100(k - m)] / (100 + m) %
E. [100(k - m)] / (100 + k + m) %

Solution:

To start, we need to define a few variables.

p = price per share of stock X

e = earnings per share of stock X

We are given that the price per share of stock X increased by k percent. We can express this as:

p(1 + k/100) = p((100 + k)/100)

We are also given that the earnings per share of stock X increased by m percent. We can express this as:

e(1 + m/100) = e((100 + m)/100)

Finally, we are asked by what percent the ratio of the price per share to earnings per share increased. We'll set up our two ratios and then plug those into the percent change formula. While the math that is produced here may seem a bit complicated, it is not too bad as long as we take our time and stay focused.

Image

Answer:D

Scott Woodbury-Stewart
Founder and CEO
[email protected]

Image

See why Target Test Prep is rated 5 out of 5 stars on BEAT the GMAT. Read our reviews

ImageImage
Join the discussion

by Jim@StratusPrep » Fri Jul 10, 2015 4:47 am
Uh.... I would stay away from the algebra. It's too easy to make a mistake. Have a look at this...
Image

Image

Image

Image

Image

Image

Image
[/img]
GMAT Answers provides a world class adaptive learning platform.
-- Push button course navigation to simplify planning
-- Daily assignments to fit your exam timeline
-- Organized review that is tailored based on your abiility
-- 1,000s of unique GMAT questions
-- 100s of handwritten 'digital flip books' for OG questions
-- 100% Free Trial and less than $20 per month after.
-- Free GMAT Quantitative Review

Image
Join the discussion

by GMATGuruNY » Fri Jul 10, 2015 5:16 am
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-m)/100+k %
D) 100(k-m)/100+m %
E) 100(k-m)/100+k+m %
Original ratio:
Let the original price = 100 and the original earnings = 100.
Resulting ratio:
price/earnings = 100/100 = 1.

New ratio:
Let k=200 and m=100.
Since the price increases by k=200%, the new price = 100 + (200/100)(100) = 300.
Since the earnings increase by m=100%, the new earnings = 100 + (100/100) = 200.
Resulting ratio:
(new price)/(new earnings) = 300/200 = 1.5.

Since the old ratio = 1 and the new ratio = 1.5, the ratio increases by 50%. This is our target.
Now plug k=200 and m=100 into the answers to see which yields our target of 50.
Only D works:
100(k-m)/(100+m) = (100)(200-100) / (100+100) = 50.

The correct answer is D.
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.

As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.

For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3
Join the discussion

by Brent@GMATPrepNow » Fri Jul 10, 2015 6:57 am
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-m)/100+k %
D) 100(k-m)/100+m %
E) 100(k-m)/100+k+m %
Another approach is to plug in values.

Let $100 be the original price per share of Stock X
Choose a "nice" value for k. How about k = 200
So, after a 200% increase, the new price per share = $300

Let $100 be the original earnings per share of Stock X
Choose a "nice" value for m. How about m = 100
So, after a 100% increase, the new earnings per share = $200

Original ratio of price/earnings = $100/$100 = 1
New ratio of price/earnings = $300/$200 = 1.5

By what percent did the ratio of price per share to earnings per share increase?
So, the percent increase (from 1 to 1.5) is 50%.
In other words, when k = 200 and m = 100, the ratio increases 50%

Now, plug in 200 for k, and 100 for m, and look for the answer choice that also yields 50%.

A. k/m = 200/100 = 2 (nope)

B. (k - m) = 200 - 100 = 100 (nope)

C. [100(k - m)] / (100 + k) = 10,000/300 = 33.333 (nope)

D. [100(k - m)] / (100 + m) = 10,000/200 = 50 GREAT!

E. [100(k - m)] / (100 + k + m) = 10,000/400 = 25 (nope)

Answer: D

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
Image
Join the discussion