Step-by-step explanation:
x×k = y
14×k = 12
k = 12/14 = 6/7
so, the equation is
x × 6/7 = y
or
y = 6x/7
or
y = 6/7 x
$4 is the original price of the jar consisting of peanut butter so therefor it = 100%. It's for sale at $3.60, so we divide $4 by 100% so we get the percentage for each cent and then we times it by 3.60 to get the percentage for $3.60 which is 90%. Now we subtract 90% from 100% to get the discounted percentage for 40cents :)