144. Solving a chemistry problem

81. Option 3
A portion of the zeolite weighing 0.5000 g was fused with soda in a platinum crucible, dissolved in HCl (1: 3) and transferred to a volumetric flask with a capacity of 200.00 ml. Potassium was determined by the method of calibration curve. Received the following data for the construction of the calibration curve:
C (K), mg / l 10.00 20.00 30.00 40.00 50.00
I, μA 12 25 34 43 50
Determine the mass fraction (%) of potassium in the samples for the following options:
Option 3
I, µa = 40