Life expectancy among adults 45 and 65 years
of age by family income, sex, and race: United States, average annual
1979-89 
单选题
A sequence of numbers begins 1, 1, 1, 2, 2, 3 and then repeats this pattern forever. What is the sum of the 135th, 136th, and 137th numbers in the sequence?
【正确答案】
C
【答案解析】Since the pattern has six digits, divide 135 by 6. The quotient is 22 and the remainder is 3. Since 22 × 6 = 132, the 132nd number completes the pattern for the 22nd time. So the 133rd, 134th, and {{U}}135{{/U}}th numbers are Is, and the {{U}}136{{/U}}th and {{U}}137{{/U}}th are 2s; and their sum is {{U}}1{{/U}}+{{U}}2{{/U}}+{{U}}2{{/U}}=5,
单选题
In the figure above, the diameter of the circle is 20 and the area of the shaded region is 80π. What is the value of a + b + c + d?
【正确答案】
E
【答案解析】Since the diameter of the circle is 20, the radius is 10 and the area is 100π. Since the area of the shaded region is 80π, it is
 of the circle, and the white area is  of the circle. So the sum of the measures of the two white central angles is  |