Given data: 6,6,9,8,x,6,3,4,8. If the mode is 6, then x = ?

Given:
Data set: 6,6,9,8,x,6,3,4,8
The mode of the data set is 6.

Concept Used:
The mode of a data set is the value that appears most frequently.

Data set: 6,6,9,8,x,6,3,4,8

6 appears 3 times
9 appears 1 time
8 appears 2 times
3 appears 1 time
4 appears 1 time

The frequency of 6 in the data set is 3. For the mode to be 6, x must not appear more than 3 times. The possible values for x that will maintain 6 as the mode.

If x = 6, the frequency of 6 becomes 4, which is still greater than any other frequency.

So, x = 6 to maintain 6 as the mode.

Thus, the correct answer is (d).