Cost of a Notebook Calculation

What is the cost of a notebook based on the given purchases?

A) $3.50

B) $4.00

C) $4.25

D) $4.50

Final Answer:

To find the cost of a notebook, we can solve a system of equations based on the purchases of Ana and Carlos. Given that Ana bought a pen and a notebook for $6.00, and Carlos bought a pen and a T-shirt for $11.75, we can determine that the cost of a notebook is $4.25.

Explanation: To determine the cost of a notebook, we need to solve a system of equations. Let's assign variables to the prices of the pen, notebook, and T-shirt. Let x be the price of the pen, y be the price of the notebook, and z be the price of the T-shirt.

We can set up the following equations based on the given information:

1. x + y = 6 (Ana's purchase)
2. x + z = 11.75 (Carlos's purchase)

From equation 1, we can express x in terms of y as x = 6 - y. Substituting this into equation 2, we get (6 - y) + z = 11.75. Simplifying this equation, we find that z = 5.75 + y.

Since Helen bought a notebook, we can assume she did not purchase the pen or the T-shirt, so her purchase only includes the price of a notebook. Therefore, y = 4.25. Hence, the cost of a notebook is $4.25.