Each of the integers from 1 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 10?  Choose the correct choice from the following answers
A) 3 B) 4 C) 5 D) 6 E) 7
Answer is 6. In the worst case, you could end up drawing 1,2,3,4,5. 7th draw will result in either of 6,7,8,9 which would result in the numbers adding to 10.   6
<result>D</result>
Each of the integers from 1 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 10?