John want to buy a $100 Trouser at the store, but he think itâ€™s too expensive. Finally, it goes on sale for $70. What is the percent decrease?
Choose the correct option.
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€“ 70 = 30. The â€œoriginalâ€ is our starting point; in this case, itâ€™s 100. (30/100)*100 = (0.3)*100= 
<gadget id="calculator">(0.3)*100</gadget>
<output>30</output>
30%.   30%
<result>B</result>
John want to buy a $100 Trouser at the store, but he think itâ€™s too expensive. Finally, it goes on sale for $70. What is the percent decrease?