Calculate Margin percentage  

Careful, do not find the difference between $3 and $1.80 and say that the percent decrease is $1.20.
Use this formula to find the percent decrease.
Percent decrease = (Site Price $3 – Cost $1.80) ÷ Older.
= (3 – 1.80) ÷ 3
= .40 = * 100 = 40%