John want to buy a $100 Trouser at the store, but he think itâ€™s too expensive. Finally, it goes on sale for $80. What is the percent decrease?	Choose the correct choice
A) 20 %	B) 30 %	C) 40 %	D) 50 %	E) 60 %

Rationale: "the is always the difference between our starting and ending points . in this case , it â € ™ s 100 â € “ 80 = 20 . the â € œ original â €  is our starting point ; in this case , it â € ™ s 100 . ( 20 / 100 ) * 100 = ( 0.2 ) * 100 = 20 % . a"
Answer: A