The average of the known data 1, 2, X and 5 is 2.5, and the median and mode of this group of data are () A. 2 and 2b. 2 and 2.5c. 1 and 2

The average of the known data 1, 2, X and 5 is 2.5, and the median and mode of this group of data are () A. 2 and 2b. 2 and 2.5c. 1 and 2

2.5 × 4 - (1 + 2 + 5) = 10-8 = 2, this group of numbers is: 1, 2, 2, 5, 2, the most frequent occurrence, is the mode of this group of numbers