Let f (t) be the number of ducks in a lake t years after 1990. a. What does the statement f (4) = 31 mean? There will be 31 ducks in the lake 4 years from now. In 31 years, there will be 4 ducks in the lake. In 1994, there were 31 more ducks than in 1990. In 1994, there were 31 ducks in the lake. b. What does the statement f (10) = 37 mean? Every 10 years, there are 37 more ducks in the lake. In the year 2000, there were 37 ducks in the lake. In 37 years, there will be 10 ducks in the lake. There will be 37 ducks in the lake 10 years from now