Westonci.ca is your go-to source for answers, with a community ready to provide accurate and timely information. Join our Q&A platform to connect with experts dedicated to providing accurate answers to your questions in various fields. Explore comprehensive solutions to your questions from knowledgeable professionals across various fields on our platform.

. Marco bought pens and pencils with his company's name and website address to give away to people at a festival. He bought a total of 300 pens and pencils together and spent $62.50. If pencils cost $0.15 each and pens cost $0.25 each, how many pens did Marco buy? A. 175 B. 165 C. 140 D. 130 E. 125

Sagot :

He bought a total of 300 pens and pencils and spend $62.50.

Each pen cost $0.25 and each pencil cost $0.15.

Lets call x the number of pens and y the number of pencils.

Then, as the sum of x and y is 300, we can write:

[tex]x+y=300[/tex]

The total cost is $62.50, which is the result of adding each individual cost: the price multiplied by the quantity.

Then, we can write:

[tex]0.25x+0.15y=62.50[/tex]

We use the information of the first equation to define y in function of x and replace in the second equation:

[tex]x+y=300\longrightarrow y=300-x[/tex][tex]\begin{gathered} 0.25\cdot x+0.15\cdot(300-x)=62.50 \\ 0.25x+45-0.15x=62.50 \\ 0.10x=62.50-45 \\ 0.10x=17.5 \\ x=\frac{17.5}{0.10} \\ x=175 \end{gathered}[/tex]

Knowing x, we can calculate y:

[tex]y=300-x=300-175=125[/tex]

He bought 125 pencils and 175 pens.

Answer: A. 175