Answer:
D. 53
Explanation:
"without the outlier"...the outlier is 91 because it is way higher than all the other number which are in the 50's. So you just find the mean of 51, 54, 55, and 52.
To do this, you add all the numbers together and divide by how many numbers there are.
51+54+55+52=212
212/4=53
The mean is 53