Final answer:
The number of hits made in a round of Hacky Sack can vary, but based on the given data, the average is 19 hits per round.
Step-by-step explanation:
The number of hits made in a round of Hacky Sack can vary depending on the skill level of the players and the rules being followed. However, based on the information provided, we can calculate the average number of hits. The given data shows the number of hits made in multiple rounds, so we can add up all the values and divide by the total number of rounds to find the average.
Adding up all the values: 17+20+21+18+20+20+20+18+19+19+20+19+21+20+18+20+20+19+18+19 = 388
There were 20 rounds in total, so the average number of hits per round is 388/20 = 19.4
Since the number of hits should be a whole number, we can round the average to the nearest whole number. 19.4 rounds to 19. Therefore, the answer is a) 19.