The relative uncertainty in the volume is
\n\\[ R_{u_v} = \\frac{\\var{tolerance}\\text{ (mL)}}{\\var{flaskvolume*1000}\\text{ (mL)}} = \\var{relative_uncertainty_volume} \\]
\nThe relative uncertainty in the mass, for a measured mass of $m$ mg, is
\n\\[ R_{u_m} = \\frac{\\var{accuracy}\\text{ (mg)}}{m \\text{ (mg)}} \\]
\nThe less solute you weigh out, the greater the relative uncertainty in the mass. So, the least solute you can weigh is the amount at which the relative uncertainties in volume and mass are equal.
\nThe point at which the two uncertainties are equal is
\n\\begin{align}
R_{u_v} &= R_{u_m} & \\iff \\\\
\\var{relative_uncertainty_volume} &= \\frac{\\var{accuracy}}{m} & \\iff \\\\
m &= \\frac{\\var{accuracy}}{\\var{relative_uncertainty_volume}} & \\implies \\\\
m &= \\var{min_solute} \\text{ mg} \\\\
&= \\var{min_solute/1000} \\text{ g}
\\end{align}
As you weigh out more solute, the relative uncertainty in the mass is:
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\n[[0]]g (to 3 decimal places)
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