If 2x=5, 3y=4 and 4z=3 what is the value of 24xyz

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.

15/16 as a decimal rounded to the nearest hundredth

How many sides does a regular polygon have if each exterior angle measure is 45 degrees explain your answer, i really don't understand this.