Not sure about this....but here's my rationale
We know that we have 15 scores of 10
Since the mode is 7 we need to have 16 scores of 7 (and no more than this )
The median is 9, so the 20 and 21st scores must be 9....to keep the average as small as possible
And the other 3 scores need to be as small as possible so let them =1
We have
1, 1, 1, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7 ,7, 7, 9 ,9, 9, 9, 9, 9,10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10
Median = 9
Mode = 7
Mean = 7.975 = 8
