I need help with these study questions.

1. Why is the price of gold the same in London as New York?
2. The overall divorce rate (i.e., the number of divorces divided by the number of marriages) has fallen dramatically since the 1980s. Since the rate is calculated relative to the number of marriages, this cannot be chalked up to fewer marriages. People who get married today have a much higher likelihood of staying married relative to thirty years ago. How might you use our economic principles to explain this result? Explain.
3. Woody and Margot have been married for 25 years. Woody is having a conversation with his best friend and explains that the cost of staying with Margot is just too high and he wishes he could ask for a divorce. When his friend asks why he has not done so, Woody responds "Because we have been married so long." Do you think Woody is acting rationally? Why or why not? Explain.