Word Problem:
In one town, the number of pounds of sugar consumed per person per year has a mean of $8$ pounds and a standard deviation of $1.7$ pounds. Henry consumed $11$ pounds of sugar last year. How many standard deviations from the mean is that?
The answer is: $1.76$ standard deviations above the mean, but how?
By definition $z={X-\mu \over \sigma}={11-8 \over 1.7}=1.76$ We have expressed the difference in terms of standard deviations.