(Solved): A sample of bacteria taken from a river has an initial concentration of \( 5.4 \) million bacteria ...

A sample of bacteria taken from a river has an initial concentration of \( 5.4 \) million bacteria per milliliter and its concentration triples each week. (5 points each) a) Find an exponential model \( f \) that calculates the concentration after \( x \) weeks. b) Estimate the concentration after \( 2.6 \) weeks. c) Estimate when this population will reach 17 million.