The mean of 20 numbers is 18. if 3 is added to each of the first ten numbers, find the mean of the new set of 20 numbers.

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?

Solve each quadratic equation by factoring and using the zero product property. x^2 + 18x = 9x

You use technology ans find a sum of 6.712e-8. write this sum in standard form