The amount of sales tax varies directly with the cost of the purchase. If the sales tax is $3.80 on a purchase of $76 what would be the sales tax on a purchase of $46

Respuesta :

Answer:

The sales tax is equal to [tex]\$2.3[/tex]

Step-by-step explanation:

we know that

A relationship between two variables, x, and y, represent a proportional variation if it can be expressed in the form [tex]y/x=k[/tex] or [tex]y=kx[/tex]

Let

y-----> the cost of the purchase

x ----> the sales tax

step 1

Find the value of k

For [tex]y=76, x=3.80[/tex]

substitute

[tex]k=y/x[/tex]

[tex]k=76/3.8[/tex]

[tex]k=20[/tex]

The linear equation is equal to

[tex]y=20x[/tex]

step 2

what would be the sales tax on a purchase of $46

For [tex]y=46, x=?[/tex]

substitute in the equation

[tex]46=20x[/tex]

[tex]x=46/20[/tex]

[tex]x=\$2.3[/tex]

Answer:

$2.30

Step-by-step explanation:

We have been given that the amount of sales tax varies directly with the cost of the purchase.

We know that a direct variation in in form [tex]y=kx[/tex], where, y varies directly with x and k is constant of variation.

First of all, we will find constant of variation as:

[tex]\text{Sales tax}=k*\text{Cost of purchase}[/tex]

[tex]\$3.80=k*\$76[/tex]

[tex]\frac{\$3.80}{\$76}=\frac{k*\$76}{\$76}[/tex]

[tex]0.05=k[/tex]

To find the amount of sales tax on a purchase of $46, we will substitute [tex]k=0.05[/tex] in our equation as:

[tex]\text{Sales tax}=0.05*\$46[/tex]

[tex]\text{Sales tax}=\$2.30[/tex]

Therefore, the sales tax would be $2.30.