Answer:
21
Step-by-step explanation:
To find the median of the given set, you narrow the options down and get n+7 and n+8 as the middle numbers. The average of those two is n+7.5, so that's the median.
n+7.5=20
n=12.5
Substitute n into the values.
12.5, 14.5, 15.5, 17.5, 19.5, 20.5, 23.5, 26.5, 28.5 and 31.5.
Add everything together to get 210. Divide 210 by 10, the number of values, and you end up with 21.
