PREP数学

麦兜woo

1.Amy's grade was the 90th percentile of the 80grades for her class. Of the 100grades from another class, 19 were higher than Amy's , and the rest were lower. If no other grade was the same as Amy's grade, then Amy's grade was percentile of the grades of the two class combined?
A. 72nd
B. 80th
C.81st
D.85th
E.92nd
答案选D

2. On the number line above, the segment from o to 1 has been divided into fifths, as indicated by the large tick marks, and also into sevenths, as indicated by the small tick marks. What is the least possible distance between any two of the tick marks?
A.1／70B. 1／35
C. 2／35
D. 1／12
E. 1／7
图不方便弄上来，很简单画条直线0到1，再在这条直线上划分成5段和7段
答案是B,可我算出是C，不是把1／5-1／7就是最小距离吗？

E. 1／7
图不方便弄上来，很简单画条直线0到1，再在这条直线上划分成5段和7段
答案是B,可我算出是C，不是把1／5-1／7就是最小距离吗？