Some plese help i dont no what it is plese plese math

An automated water dispenser fills packets with one liter of water on average, with a standard deviation of 5 milliliter. the manual says that after a year of operation the dispenser should be tested to see if it needs recalibration. a year later a number of filled packets are set aside and measured separately. it is found that the average packet now contains about 0.995 liters. does the dispenser need calibration? explain your answer.

What is the rate for one gallon of gasoline

Two numbers have a sum of -19. one number is x. what expression represents the other number?