111. Solving a chemistry problem

92. To determine potassium in grape juice by emission flame photometry, the addition method was used. For this, two solutions were analyzed:
1) 10 grape juice was diluted in a volumetric flask with a capacity of 100.
2) 2 solutions of potassium chloride with a molar concentration equal to 0.1000 mol / were added to the first solution during dilution. The microammeter readings of the photometer were 56.0 μA and 84.2 μA, respectively. Calculate the potassium content of grape juice (mg/.