Exercise 1 solution

(a) 71,531 / 27 = about 2,649 times as many observers.
(b) 52,471 / 1,823 = about 28.8 observers per place.
(c) (2,369 - 1,823) / 1,823 = 546 / 1,823 = 0.2995, so about 30% more places.