Mega mart collects a sales tax equal to 1/16 of the retail price. is the amount of tax collected proportional to the cost of an item before tax is added

Mega mart collects a sales tax equal to 1/16 of the retail price.

Lets take some example

Suppose retail price = $16 then tax =

retail price = $32 then tax =

retail price = $48 then tax =

retail price = $64 then tax =

From this we conclude that ,

So, the amount of tax collected proportional to the cost of an item before tax is added

.

the first one, all those points on the line just make a strait line.