单选题
Percentage of students who reported spending time on homework
and watching television


单选题 In 1996, what percent of fourth-graders did between 1 and 2 hours of homework per day?
【正确答案】 B
【答案解析】From the top graph, we see that among fourth-graders in 1996:
25% did no homework;
55% did less than 1 hour;
5% did more than 2 hours.
This accounts for 85% of the fourth-graders;
the other 15% did between 1 and 2 hours of homework per day.
单选题 If in 1984 there were 2,000,000 eleventh-graders, and if between 1984 and 1996 the number of eleventh-graders increased by 10%, then approximately how many more eleventh-graders watched 1 hour or less of television in 1996 than in 1984?
【正确答案】
【答案解析】In 1984, approximately 540,000 eleventh-graders watched television 1 hour or less per day (27% of 2,000,000). By 1996, the number of eleventh-graders had increased by 10% to 2,200,000, but the percent of them who watched television 1 hour or less per day decreased to about 18%: 18% of 2,200,000 is 396,000. This is a decrease of 144,000, or approximately 150,000.
单选题 Which of the following expresses the area of a cir-cle in terms of C, its circumference?
【正确答案】 A
【答案解析】Since C = 2πr, then [*] and area of circle =[*]