Question

Question Lincoln bought 3 bottles of an energy drink for $4.50. Write an equation relating the total cost y to the number of energy drinks bought x.

Answer 1

y=1.5x

Explanation

Step 1

you can easily solve this by using a rule of three.

Let

Lincoln bought 3 bottles of an energy drink for $4.50

$\begin{gathered} 3\text{ bottles }\rightarrow4.5 \\ 3\rightarrow4.5 \\ \text{the proportion between the number of bottles and the price is} \\ \frac{3\text{ bottles}}{4.5\text{ usd}}=0.666 \end{gathered}$

x= the number of energy drinks bought

y=the total cost

Step 2

make the equations

the proportions must be the same, then

$\begin{gathered} \frac{x}{y}=\frac{3}{4.5} \\ \text{isolate y} \\ 4.5x=3y \\ 3y=4.5x \\ y=\frac{4.5x}{3} \\ y=1.5x \end{gathered}$

I hope this helps you