The tenth value is 15
Solution:
Given that, data set has 9 values
The mean of the set is 5
Number of values = 9 and mean = 5
The mean is given by formula:


When a tenth value is added, the mean becomes 6
Let the tenth value be "x"
New mean is given as:

The tenth value is given as:
sum of 9 terms + x = 60
45 + x = 60
x = 60 - 45
x = 15
Thus the tenth value is 15