During 2001, a stock lost 40 percent of its value. During the following year, the stock's value increased by 200 percent. Which of the following is the percent change in the stock's value during those two years?
Select:
A) 60 percent decrease  B) 40 percent decrease  C) 20 percent increase  D) 80 percent increase  E) 140 percent increase
Let the value of the stock in 2000 be 100, then in 2001 its value would be 100*(1-40/100)=100*0.6= 
<gadget id="calculator">100*0.6</gadget>
<output>60</output>
60 and in 2002 its value would be   60*(1+200/100)= 
<gadget id="calculator">  60*(1+200/100)</gadget>
<output>180</output>
180. Hence during those two years the value of the stock increased from 100 to 180, so by 80%.   Answer: 80 percent increase.
<result>D</result>
During 2001, a stock lost 40 percent of its value. During the following year, the stock's value increased by 200 percent. Which of the following is the percent change in the stock's value during those two years?