I just need the answers for number 2. The table

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?

Ariver current has a velocity of 5km/h relative to the shore, and a boat moves in the same direction as the current at 5 km/h relative to the river. how can the velocity of the boat relative to the shore be calculated?

Ablock of aluminum is dropped into a graduated cylinder with an initial volume of water at 75ml and the volumes rises to 90ml. if the block has a mass of 40.5 g what is its density ?