Three of four numbers have a sum of 22. if the average of the four numbers is 8, what is the 4th number? a. 4 b. 6 c. 8 d. 10

The sum of three number is 22, the sum of four numbers is (8*4)=32, so the 4th number is 10

The first one, i believe, would be correct. all the others have one thing in common, and that's that they have repeating numbers. in the second one, x and y have repeating 6's and 3's, and in the third, x and y have repeating 6's as well. in the last one, there are repeating 3's. the first one has no repeating numbers.