Carcass wrote:
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. \(\frac{k}{m} %\)
B. \((k – m) %\)
C. \(\frac{100(k – m)}{(100 + k)} %\)
D. \(\frac{100(k – m)}{(100 + m)} %\)
E. \(\frac{100(k – m)}{(100 + k + m)} %\)
Let's use the INPUT-OUTPUT approach.
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