NEED HELP ASAP PLEASE . End of quarter today

Evaluate the expression for the given value of the variable. 5×(h+3) for h=7

Monthly water bills for a city have a mean of $108.43 and a standard deviation of $32.09. find the probability that a randomly selected bill will have an amount greater than $155, which the city believes might indicate that someone is wasting water. would a bill that size be considered unusual?

[10 points, algebra 2]according to my answer key the restrictions are -1 and 4. but why not positive 1?