56 books;75% decrease

The classrooms are trying to raise $1,200.00 for charity. mrs. leblanc's class has raised 50%. mr. patel's class has raised $235.14 ms. warner's class has raised 1/3 as much as mrs. leblanc's class. how much more money is needed to reach the goal of $1,200.00?

How to do this , and can some one explain

The number of fish in a lake can be modeled by the exponential regression equation y=14.08 x 2.08^x where x represents the year