A friend has a 85% average before the final exam for a course. That score includes everything but the final, which counts for 15% of the course grade. What is the best course grade your friend can earn?

15 point ! ~ see if you know the answer to both you!

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.

Define multiplicative inverse. give an example of a number and its multiplicative inverse.