<p>How many gram of&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><mi>K</mi><mi>M</mi><mi>n</mi><msub><mi>O</mi><mn>4</mn></msub></math>&nbsp;should be taken to make up 250 mL of a solution of such strength that 1 mL is equivalent to 5.0 mg of Fe in&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><mi>F</mi><mi>e</mi><mi>S</mi><msub><mi>O</mi><mn>4</mn></msub></math>?</p>