Pam's suitcase can weigh up to 50 pounds. She is planning to pack 5 school books, each of which weighs 2 pounds. She will also pack 3 notebooks weighing 1 pound each, and 6 boxes of golf balls weighing 2 pounds each. Her clothing weighs a total of 16 pounds. Write and evaluate an expression to show how many pounds Pam has to pack.