Question

1. françois a acheté un appareil photo pour w dollars et une lentille pour 120\\$. si la taxe de vente était de 13\\%, combien françois a-t-il payé pour lappareil photo et la lentille, taxe incluse?

Explanation:

Step1: Find the total cost before tax

The cost of the camera is \( w \) dollars and the lens is \( 120 \) dollars. So the total before tax is \( w + 120 \) dollars.

Step2: Calculate the tax amount

The sales tax is \( 13\% \), which is \( 0.13 \) in decimal. The tax on the total before tax is \( 0.13(w + 120) \) dollars.

Step3: Find the total cost including tax

To find the total cost including tax, we add the tax to the total before tax. So the total cost \( C \) is:
\[

$$\begin{align*} C&=(w + 120)+0.13(w + 120)\\ &=(1 + 0.13)(w + 120)\\ &=1.13(w + 120)\\ &=1.13w+1.13\times120\\ &=1.13w + 135.6 \end{align*}$$

\]

Answer:

The total amount François paid is \( 1.13w + 135.6 \) dollars (or we can also write it as \( 1.13(w + 120) \) dollars).