In 2000 pizza costs 7.50 and in 2015 it costs 9.00 what is the percentage of change in the cost of the pizza

Geometry. i need step by step explanation on how to do each problem.

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?

Acoin bank containing only dimes and quarters has 12 more dimes than quarters. the total value of the coins is $11. how many quarters and dimes are in the coin bank?