Aluminum sells for $0.35 per meter. How much does a piece of aluminum 5.12 kilometers long cost?

The graph above shows how the price of cell phones varies with the demand quantity. the equilibrium price for cell phones is where both supply and demand quantities equal $100, 5,000 5,000, $100

Can someone me with questions 15 to 17 plz.

Suppose that a certain fortunate person has a net worth of $71.0 billion ($7.10×1010). if her stock has a good year and gains $3.20 billion (3.20×109) in value, what is her new net worth?