Carl thought of 5 numbers and told Danny all the sums that could be made by adding the numbers in pairs. The list of sums is given below. What are the five numbers? 6,7,8,8,9,9,10,10,11,12?

Answer 1

2,4,5,6,6 comes close. It has one 9 and two 11's
See what you can do with it.