Can someone explain how to do these i need a quick crash course

Because of your favorite lemonade it is $3.84 for 3 gallons. write this as an unit rate

Isuck at math ; ^; m a student solved this problem and said the answer is 3 feet. chase had a roll of ribbon that contained 7 7/8  feet of ribbon. he cut off one piece that was 3 5/8  feet long and another piece that was 1 1/4  feet from the roll. how much ribbon was left on the roll? is the student's answer reasonable? yes, the answer is reasonable. no, the answer is not reasonable. it should be about 2 feet. no, the answer is not reasonable. it should be about 13 feet. no, the answer is not reasonable. it should be about 4 feet.

Find the y-intercept and x-intercept for the equation 5x-3y=60 what is the y-intercept