PLZ HELPPP.3+28/z +4s use z=7 and s=5

Nikolas calculated the volume of the prism. his work is shown below.

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

Student representatives surveyed their classmates on their preference of a school mascot for a new school. the results are shown in the table below. which pair of samples seems most representative of student preference?