OG11 99 about the meaning of reading

who could tell me the meaning of "reading" in the below question? (many many thanks in advance)

On a scale that measures the intensity of a certain phenomenon, a reading of n+1 corresponds to an intensity that is 10 times the intensity corresponding to a reading of n. on that scale, the intensity corresponding to a reading of 8 is how many times as great as the intensity corresponding to a reading of 3?