I am concerned in how to do an exercise, because I don't actually know how to do it:

A 0.0500 M solution, whose solute has a molecular weight of 230, gives a reading of transmittance of 35% when using a cuvette with a path length of 1 cm and a length 270nm wave. Calculate the absorptivity

I've tried doing it before, but because I don't pay atention in class I have no formulas nor notes, my fault, but I can't ask the teacher anymore since it's Easter, thanks a lot in advance