In a psychology class, 57 students have a mean score of 96.7 on a test. Then 12 more students take the test and their mean score is 75.7. What is the mean score of all of these students together? Round to one decimal place. mean of the scores of all the students =

How many liters of peroxide should be added to 12 liters of an 8% peroxide solution so that the resulting solution contains 16% peroxide?   original added new amount of peroxide 0.96 liters x 0.96 + x amount of solution 12 liters x 12 + x 0.18 liter 1.14 liters 1.92 liters 2.10 liters