1. There are 20 plants in your garden but only enough fertilizer spray to boost 8 of them. How many ways are there to fertilize the plants?
2. How many different seven-digit phone numbers begin with 231- and contain at least one 9?
3. At a meeting of h hobgoblins and t trolls, it is decided that the collection of n chipmunk snax will be distributed in some way. Every hobgoblin must get at least one chipmunk but trolls are not required to receive chipmunks, yummy though they are. How many ways can the chipmunks be fed to the hobgoblins and trolls?