Answer:
a) A total of 27 parents will receive a call on the third round of calls. b) A total of 39 parents would've been called by the end of the third round of calls. c) There would have to be a total of between 5 and 6 rounds
Explanation:
Every time the total number of parents call 3 people, the number of parents tripled in every round.
3 to 9 to 27 to 51 to 153 to 459
Since 153 and 459 are between 5 and 6 rounds, the phone calls will stop between those 2 rounds.