Since all three decimal digits are the same, the sum of the digits is 3 times one digit.

Let each digit be the same value. The sum of 3 identical digits is 3 x that digit.
Sum of digits	=	3 x digit = 24
Each digit	=	24 / 3 = 8
The number is less than 1, so it has 0 in the ones place.
The decimal	=	0.888