Bunuel wrote:

A share of stock in Ace Enterprises cost D dollars on Jan. 1, 1999. One year later, a share increased to Q dollars. The fraction by which the cost of a share of stock has increased in the year is

A. (Q - D)/D

B. (D - Q)/Q

C. D/Q

D. Q/D

E. (Q - D)/Q

Use the first part of percent increase formula-IMO, faster

The fraction by which the price of the stock increased can be calculated with percent change / percent increase formula, except without the (* 100).

The (* 100) changes the very fraction we seek into a percent.

Percent increase:

\(\frac{(New-Old)}{Old} * 100\). Omit the * 100

Fractional increase where D is old price and Q is new price:

\(\frac{(New-Old)}{Old}=\frac{(Q - D)}{D}\)

Answer A

Choose valuesLet D dollars = 10

Let Q dollars = 15

The absolute increase in cost is 15 - 10 = 5 dollars.

5 is what fraction of original cost, 10?

\(\frac{part}{whole}=\frac{5}{10}=\frac{1}{2}\)

With D = 10, Q = 15, find the answer that yields result of \(\frac{1}{2}\)

Eliminate C and D immediately (with these numbers). The relationship between 10 and 15, regardless of which is the numerator and which is the denominator, is not 1/2

A. (Q - D)/D

\(\frac{(15 - 10)}{10}=(\frac{5}{10})=\frac{1}{2}\) MATCH

B. (D - Q)/Q

\(\frac{(10 - 15)}{15}=\) STOP. This result is negative. Indicates decrease. Prompt says increase. REJECT

E. (Q - D)/Q

\(\frac{(15-10)}{15}=(\frac{5}{15})=\frac{1}{3}\). NO MATCH

Answer A

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