Problem Solving
试题详情
题目：
Each of the integers from 0 to 9, inclusive, is written on a separate slip of blank paper and the ten slips are dropped into a hat. If the slips are then drawn one at a time without replacement, how many must be drawn to ensure that the numbers on two of the slips drawn will have a sum of 10 ?
选项:
A、Three
B、Four
C、Five
D、Six
E、Seven
答案:
E
