carcass wrote:

Judy bought a quantity of pens in packages of 5 for $0.80 per package. She sold all of the pens in packages of 3 for $0.60 per package. If Judy's profit from the pens was $8.00, how many pens did she buy and sell?

A. 40

B. 80

C. 100

D. 200

E. 400

carcass, you are a master of crafty language, and this one takes the prize.

The trap is in the second sentence: "She sold all of the pens in packages of 3 for $0.60 per package."

That sentence does not mean that all the pens she sold were in packages of 3. In fact, coupled with the implication of answers that are not multiples of 15, the sentence means just the opposite; it means "

not all the pens sold were in boxes of 3."

A quantity that can be divided evenly into 5 per package and into 3 per package must be divisible by 15. None of the answer choices offers that possibility.

So the pens Judy sold were not all in packages of 3.

We have total profit. To get the number of pens, we need Judy's cost per pen and her sell price per pen.

A package of five pens cost Judy 80 cents. \(\frac{80}{5}\) = each pen cost 16 cents.

A package of three pens sold for 60 cents.\(\frac{60}{3}\) = each pen sold for 20 cents.

Profit per pen is 20 - 16 = 4 cents' profit per pen.

Total profit = (profit per pen) * (number N of pens sold)

$8.00 = ($0.04)N

\(\frac{$8.00}{($0.04)}\) = 200

Number of pens sold: 200

Answer D