Answer:
6
Explanation:
there are 5 different possible combinations of two integers that equal 9 when you add them together:
- (0,9)
- (1,8)
- (2,7)
- (3,6)
- (4,5)
The worst case scenario is that you choose 0, 1, 2, 3, and 4, and adding any pair will not result in 9. So you will need to choose a sixth number and whichever that number is (either 5, 6, 7, 8 or 9), you will be able to add it to another one to get 9.
The best case scenario is that you choose only two and you are lucky enough to get a combination that works.
