In a survey 9 out of 15 students named math as there favorite class. express this rate as a decimal

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?

Ineed me i stuck and i don’t want to get it wrong

When 142 is added to a number the result is 64 more times the number my options are 35 37 39 41