[Problem Solving]
试题详情
题目:
There are 8 books on a shelf, of which 2 are paperbacks and 6 are hardbacks. How many possible selections of 4 books from this self include at least one paperback?
选项:
A、 40
B、 45
C、 50
D、 55
E、 60
答案:
D
The parallelogram shown has four sides of equal length. What is the ratio of the length of the shorter diagonal to the length of the longer diagonal?




