Question 855718
The combinations would be:
(6,7), (6,8), (6,9), (6,10), (6,11)
(7,8), (7,9), (7,10), (7,11) ---> Note that you don't include 7,6 since it is already counted. 6,7 and 7,6 are equivalent.
(8,9) .... through till ...(8,11)
(9,...)
(10,...)
You can fill in the rest! You will get a total of 15 ordered pairs.

Hope you got the idea :)