Solving a chemistry problem

8(1). A sample of nickel-zinc ferrite containing copper, weighing m g, was dissolved and a 100.0 ml solution was obtained. An aliquot with a volume of Val ml was placed in a separatory funnel, the necessary reagents were added, and the copper was extracted with three 10.0 ml portions of ethyl acetate. The combined extract was brought to 50.00 ml with ethyl acetate, photometered and the optical density of ACh was obtained.
Determine the mass fraction (%) of copper in ferrite, using the following data obtained under similar extraction and photometric conditions to construct a calibration graph (VCT ml of a standard CuSO4 solution, the copper concentration in which was 2 μg/ml):
m,g 0.2042
AX 0.210
VAL,ml 20.0
VCT, ml 10.0
AST 0.250