Half life of a drug in the bloodstream is nine hours what fraction of the original does remains in 12 hours and in 36 hours

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?

The focus of parabola is (-4, -5), and its directrix is y= -1. fill in the missing terms and signs in parabolas equation in standard form

On a cm grid, point p has coordinates (3,-1) and point q has coordinates (-5,6) calculate the shortest distance between p and q give your answer to 1 decimal place