Need help with word problem:

The following tables give the number of shares of stocks of certain corporations held by Adam and Bob at the end of September and October:

SeptemberAdam......... |250|500|400||IBM|GE|Walmart|

Bob........... |700|200|300|

October

Adam.........|300|400|550||IBM|GE|Walmart|

Bob.......... |800|300|250|

a) Write the matrices A and B giving the stock portfolios of Adam and Rob at the end of September and the end of October, respectively.

b) Find a matrix C reflecting the change in the stock portfolios of Adam and Bob between the end of September and the end of October.

c) If the prices (in dollars per share) of stocks IBM, GE, and Walmart at the close of the stock market on October 31 were $110, $50, and $60, respectively, use the matrix operation to find the values of the portfolios of Adam and Bob in the form of a matrix.