Topic: system of linear equation and matrices
1)a minor leagues basketball park has 7000 seats. box seats cost $6, grandstand seats cost $4, and bleacher seats cost $2. when all seats are sold, the revenue is $26,4000. if the number of box seats is one-third the number of bleacher seats, how many seats of each type are there?
2) makayla borrows $10,000. some it from her friend at 8% annual interest, twice as much as that of her bank at 9%, and the reminder from her insurance company at 5%, she pays a total of $830 in interest for the first year. how much did she borrow from each source?