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.