XDF教程PS196/211的题干不明白，请指教！

憨憨

196. Each of the integers from 0 to 9,  inclusive,  is written on a seperate slip of blank paper and the ten slips are dropped into a hat. if the slips are then drawn on 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?

A. three    B. Four   C. Five   D. six  E. Seven

211. If the number of square units in the area of circle C is twice the number of linear units in the circumference of C, What is the number of square units in the area?

A. 4   B. 8   C. 4pai   D. 8pai   E. 16pai

以上两道题没有读懂请指教。

winners

 

QUOTE:

without replacement, how many must be drawn to ensure that the numbers on two of the slips drawn will have a sum of 10?

意思是一次必须拿几张纸片（没有更换的情况），才能保证拿出的纸片中其中两张纸片上的数和为10的。

QUOTE:

211. If the number of square units in the area of circle C is twice the number of linear units in the circumference of C, What is the number of square units in the area?
A. 4   B. 8   C. 4pai   D. 8pai   E. 16pai

圆C的面积的数字是该圆圆周数字的两倍

mereiful

QUOTE:

QUOTE:

without replacement, how many must be drawn to ensure that the numbers on two of the slips drawn will have a sum of 10?

QUOTE:

without replacement, how many must be drawn to ensure that the numbers on two of the slips drawn will have a sum of 10?

QUOTE:

without replacement, how many must be drawn to ensure that the numbers on two of the slips drawn will have a sum of 10?

QUOTE:

without replacement, how many must be drawn to ensure that the numbers on two of the slips drawn will have a sum of 10?

意思是一次必须拿几张纸片（没有更换的情况），才能保证拿出的纸片中其中两张纸片上的数和为10的。

without replacement 没有更换的情况

就是指不放回，对么？！

winners

QUOTE:

without replacement 没有更换的情况

就是指不放回，对么？！

对，就是这意思，不放回的表达比较地道，呵呵，没想起来。