What is the mode of the following data?

4, 6, 5, 9, 3, 2, 7, 7, 6, 5, 4, 9, 10, 10, 3, 4, 7, 6, 9, 9

9

4 appears 3 times.

6 appears 3 times.

5 appears 2 times.

9 appears 4 times.

3 appears 2 times.

2 appears 1 time.

7 appears 3 times.

10 appears 2 times.

Mode = maximum frequency

We can see that, 9 appears 4 times. So this will be mode of this question.