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 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 12?
Choose the correct answer.
A) 8
B) 4
C) 5
D) 6
E) 7
i'm not sure i got the question right, if it is what i think it is, then 8 should be the right answer   0,1,2,3,4,5, will not have 2 slip sum of 10, add another (either 6,7,8 or 9) and we'll have a pair with sum 12   8ns:8
<result>A</result>
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 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 12?