Answer:
14
Explanation:
If you want to solve this question, you would need to know the sum of your number right now and after you add the blank number.
First one is: 8 + 4 + 11 + 13 = 36.
Second one: Sum = mean x [how many numbers there are], which means:
sum = 10 x 5 = 50.
Then, subtract the 36 from 50, and you get the answer: 14.