Find mathematical model,function, & sales tax

Question

State sales tax S is directly proportional to retail price p. An item that sells for 152dollars has a sales tax of 12.32 dollars.

find a mathematical model that gives the amount of sales tax S in terms of the retail price p.

function: S (p)

what is the sales tax on a 300 dollars purchase. Round to the nearest cent

the sales tax on a 300 Dollar purchase is ?

Answer 1

S = k P

12.32 = k ( 152)

12.32/ 152 = k

k = 0.08105263157894736842105263157895....

So

S(p) = kP for k defined above

the sales tax is rougly 8.1053- %

So for a $300 purchase, when p=300,

S(300) = 24.315789473684210526315789473684

or $14.32

You can also do:

12.32 / 152 = ? / 300