The average number of pages in a mystery book is 220 with a standard deviation of 20. Using Chebyshev's Theorem, what is the range of values in which at least 88.89% of the data will lie?

The choices are:

180-260
160-280
140-300
200-240

The correct answer is 160-280, but I am just no sure how to reach this. Any help would be greatly appreciated!!! Thanks

Oso