Read the following SAT test question and then click on a button to select your answer.
A biologist conducts a study regarding an invasive species, the Gupta fly, in the city of Porto Alegre, Brazil. The flies were sampled from three different parks in 2001 and 2002.
Frequency of Sampled Gupta Flies in Porto Alegre by Year
Based on the information in the table, as a percentage, approximately what is the probability that one of the sampled Gupta flies in 2001 was found in either the Botanical Garden or Farroupilha Park?
A.33%
B.50%
C.67%
D.77%
答案：C
解析：
Choice C is correct. Using the information provided in the table, we find:
The total number of Gupta flies sampled in 2001 is 2604+2681+2640=7925.
The number of Gupta flies that were sampled in either the Botanical Garden or
Farroupilha Parkis 2604+2681=5285.
The probability that one of the sampled Gupta flies in 2001 was found in either
the Botanical Garden or Farroupilha Park is the ratio of the number of Gupta flies sampled in these two parks over the total number of Gupta flies sampled in 2001.
Calculate this ratio as a percentage: Probability=5285/7925≈0.67=67%
Therefore, the probability that one of the sampled Gupta flies in 2001 was found
in either the Botanical Garden or Farroupilha Park is approximately 67%.
重点单词：
invasive [in'veisiv] adj. 侵略性的;攻击性的
frequency ['fri:kwənsi] n. 频繁，频率
species ['spi:ʃiz] n. (单复同)物种，种类
calculate ['kælkjuleit] v. 计算，估计，核算，计划，认为
multiple ['mʌltipl] adj. 许多，多种多样的
probability [.prɔbə'biliti] n. 可能性，或然率，机率
approximately [ə'prɔksimitli] adv. 近似地，大约
