Simon decided to invest $8,000 in the stock market one day early in 2008. Six months after he invested, on July 17, the stocks he had purchased were down 50%. Fortunately for Simon, from July 17 to October 17, the stocks he had purchased went up 75%. At this point, Simon has:

At this point, Simon has lost $1,000 of his money.

Explanation:

This can be determined by calculating the current value of Simon's investment as follows:

Initial amount invested = $8,000

Value of the investment on July 17 = Initial amount invested * (100% - Percentage of loss) = $8,000 * (100% - 50%) = $4,000

Value of the investment on October 17 = Value of the investment on July 17 * (100% + Percentage of increase) = $4,000 * (100% + 75%) = $7,000

Amount of loss on October 17 = Initial amount invested - Value of the investment on October 17 = $8,000 - $7,000 = $1,000

Therefore, at this point, Simon has lost $1,000 of his money.