15 of the students in a Chemistry class passed a Chemistry test. If these students are 75% of all the students in the class, how many
students are in this Chemistry class?

Dean and karlene get paid to write songs. dean is paid a one-time fee of $20 plus $80 per day. karlene is paid a one-time fee of $25 plus $100 per day. write an expression to represent how much a producer will pay to hire both to work the same number of days on a song.