1. There are (1592) stocks and (471) funds listed on the two major stock exchanges of Shanghai and Shenzhen.

February. On September 13, Mr. Zhang bought an oversold stock at a price of 4.8 yuan. On the second day, suppose the stock rose by 0.42 yuan. What percentage did it increase? Is this percentage the same as the increase or decrease? Why?

0.42/4.8=0.0875, which is 8.75%. This percentage is the rise or fall, because the two major exchanges in Shanghai and Shenzhen now have a 10% rise and fall limit for non-S and non-ST stocks.

3. At 3:00 pm on September 15th, Mr. Zhang’s stock had a cumulative increase of 15%. If he buys 20,000 shares, how much profit has he made now?

4.80×0.15×20000=14,400 yuan

Now he has made a profit of 14,400 yuan.

IV. Around 1:00 pm on September 17, Mr. Zhang promptly sold his stocks and gained 15,000 yuan from the face value of the stocks. What was the stock price at this time?

4.815000/20000=5.55 yuan

The stock price at this time is 5.55 yuan.

The above calculation ignores transaction costs.