Suppose you have a two-stock portfolio consisting of Apple and Tesla stock. The portfolio weight of Apple is 25% and the rest is Tesla. The volatility of annual returns is 35% for Apple and 60% for Tesla. The correlation coefficient between the two stocks' returns is 0.22. What's the volatility of your portfolio?

Asupermarket has been experiencing long lines during peak periods of the day. the problem is noticeably worse on certain days of the week, and the peak periods are sometimes different according to the day of the week. there are usually enough workers on the job to open all cash registers. the problem is knowing when to call some of the workers stocking shelves up to the front to work the checkout counters. how might decision models the supermarket? what data would be needed to develop these models?