C. Solve the following.

For 11-15. Students at ISNHS elect a student council.

11. If DJ, Lei, JM, and Sey are all on the council, determine the number of ways that
they can fill the positions of president and vice-president.
12. how many different signals each consisting of 7 lighted colored bulbs arranged
vertically, can be formed from a set of 2 blue bulbs, 4 yellow bulbs and a red bulb?
13. A food chain serves 2 appetizers, 5 main dishes, 2 salads and 3 desserts. How
many different meals can be ordered?
14. How many ways can the letters of ABRACADABRA be arranged?
15. In how many ways can 8 children join hands to form a ring?​