In which of the following will you be able to buy the lowest cost per pencil?

store a
$110 for 88 pencils.

store b
c = 1.10p, where c is the total cost of the pencil and p is number of pencils

store c
no. of pencils.
25 = $50.00
32 = $64.00
56 = $112.00

store d
(look at the graph)

Monthly water bills for a city have a mean of $108.43 and a standard deviation of $36.98. find the probability that a randomly selected bill will have an amount greater than $173, which the city believes might indicate that someone is wasting water. would a bill that size be considered unusual?