3. Sean, Kevin and Bill take classes at both JJC and CSU. Sean takes 8 credits at JJC and 4 credits at CSU; Kevin takes 10 credits at JJC and 6 at CSU; Bill takes 6 credits at JJC and 4 at CSU; the cost per credit at JJC is $103 and at CSU is $249.

a) Write a matrix A that gives the credits each student is taking and B that gives the cost per credit at each school.

b) Find the dimension of A and B.

c) Find the product AB and the names of its rows and columns.