See the diagram on the following page for information to answer the questions.
单选题 In the period from 1979-1989, on average, how much longer, in years, could a 45-year old Black man with a family income in excess of $25,000 expect to live than a 45-year old Black man with a family income of less than $10,000?
【正确答案】 C
【答案解析】From the lower graph, we can see that the life expectancy at age 45 for Black men with family incomes below $10,000 was 25, whereas for those whose family income was $25,000 or more, their life expectancy was 33 years: a difference of 8 years.
单选题 For which of the following groups did family income have the least significance in affecting life expectancy?
【正确答案】 E
【答案解析】The line segments constituting the graph of life expectancy for White women at age 65 are virtually horizontal. At all incomes, these women have a life expectancy of about 20 years. For none of the other categories does family income have as small an impact on life expectancy.
单选题 At Tyler High School, there are twice as many girls as boys on the yearbook staff. At one staff meeting, the percentage of girls attending was twice the percentage of boys. What percent of those attending the meeting were boys?
【正确答案】 A
【答案解析】Even if you can do the algebra, this type of problem is easier if you use TACTIC 2, Chapter 11. Find some easy-to-use numbers. Assume that there are 100 girls and 50 boys on staff and that 20% of the girls and 10% of the boys attended the meeting. Then, 20 girls and 5 boys were there, and 5 is 20% of 25, the total number attending. **Of course, you can do this algebraically. If x represents the number of boys on staff, then 2x is the number of girls. If y% of the boys attended the meeting, then 2y% of the girls did. So, the number of boys attending was whereas the number of girls attending was . Therefore, there were 4 times as many girls in attendance as boys: of those at the meeting were girls and