Question

State sales tax S S is directly proportional to retail price p p . An item that sells for 142 142 dollars has a sales tax of 12.32 12.32 dollars. Find a mathematical model that gives the amount of sales tax S S in terms of the retail price p p .

Answer 1

Answer:
`S=0.087p` .

Explanation:

Equation for direct proportion:

y=kx

, where x= independent variable ,

y=dependent variable.

k= proportionality constant

Here, State sales tax S is directly proportional to retail price p.

Also, dependent variable= S, independent variable =p

Required equation: S= kp

Put S= 12.32 and x= 142

`S=12.32=k(142)\\\\\Rightarrow\ k=(12.32)/(142)\approx0.087`

Hence, the required equation is
`S=0.087p` .