A certain radioactive isotope has leaked into a small stream. hundred days after the​ leak, ​% of the original amount of the substance remained. Determine the​ half-life of this radioactive isotope.

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.