344 students, 326 students present what percent was present

Adam used 1072.4 gallons of water over the course of 7 days. how much water did adam use, on average, each day?

Tomas used 3 1/3 cups of flour and now has 1 2/3cups left. which equation can he use to find f, the number of cups of flour he had to begin with? f+3 1/3=1 2/3 f-3 1/3=1 2/3 3 1/3f=1 2/3 f/3 1/3=1 2/3

Can someone me with #s 8, 9, and 11. with just one of the three also works. prove using only trig identities.