John want to buy a $100 Trouser at the store, but he think itâ€™s too expensive. Finally, it goes on sale for $50. What is the percent decrease?  Choose the correct choice from the following choices: A) 20% B) 30% C) 40% D) 50% E) 60%
The is always the difference between our starting and ending points. In this case, itâ€™s 100 â€“ 50 = 40. The â€œoriginalâ€ is our starting point; in this case, itâ€™s 100. (50/100)*100 = (0.5)*100= 
<gadget id="calculator">(0.5)*100</gadget>
<output>50</output>
50%.   50%
<result>D</result>
John want to buy a $100 Trouser at the store, but he think itâ€™s too expensive. Finally, it goes on sale for $50. What is the percent decrease?