Using the mean concept, it is found that the value of the number that was removed was of 4.
<h3>What is the mean?</h3>
The mean of a data-set is given by the <u>sum of all observations in the data-set divided by the number of observations</u>.
The mean of five numbers is 8, hence, the sum of the numbers is given by:
S = 5 x 8 = 40.
If one of the five numbers is removed, the mean becomes 9, hence, the sum of the four numbers is given by:
S = 4 x 9 = 36.
The difference is:
40 - 36 = 4.
Hence, the value of the number that was removed was of 4.
More can be learned about the mean concept at brainly.com/question/25122507
#SPJ1