constant of proportionality

Question

The cost of 3 pounds of grapes is $6.57.  What is the constant of proportionality that relates the cost in dollars, y, to the number of pounds of grapes, x?

Answer 1

i'm not 100% correct, but this is what I believe

 

proportionality is where k = y/x  and k is the proportionality constant

 

$6.57 : 3 pounds of grapes 

y dollar : x pounds of grapes

 

so the proportion is

 

6.57         y

____  =  ___

  3            x

 

6.57x

_____  = y

   3

 

2.19x = y

 

 

so k = 2.19