Can someone help me with number 3?

Abacteria population is tripling every hour. by what factor does the population change in 1/2 hour? select all that apply

0if x and y vary inversely and y=6 as x=7, what is the constant of variation?

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.