Answer:
Step-by-step explanation:

$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 :)
$20×.25=$5
$20-$5=$15
$15×.15=$2.25
$15+$2.25=$17.25
$17.25 is your answer
No.5=1/3x=21
So x is twenty one21