Need some help with this Operations Research question

Our manufacturing plant produces bookshelves, couches, and worktables. We have 400 hours of labor that are available to us each week, and 1000 units of lumber as raw materials. Each bookshelf produced yields a profit of $6, consumes 12 hours of labor, and 40 units of lumber. Each couch yields a profit of $5, consumes 14 hours of labor, and 22 units of lumber. Each worktables yields a profit of $8, consumes 16 hours of labor, and 60 units of lumber. Write a linear program to determine how many bookshelves, couches, and worktables should be produced to maximize profits, subject to labor and lumber restrictions. (You may allow fractional production; do not compute the optimal solution.)