Final answer:
The question deals with unit conversion from micrograms to grams using a known ratio where micrograms are converted to grams by multiplying by the inverted ratio of 1 g / 10^6 µg.
Step-by-step explanation:
The student's question references McGugan v Smith, which might seem to imply a legal case, but the context given indicates a problem involving unit conversion, specifically converting micrograms (µg) to grams (g). The known ratio is based on the definition that one microgram is equal to 10-6 grams. To convert 1.3 × 107 µg into grams, you would need to set up a conversion factor such that micrograms are in the denominator and grams are in the numerator to get the correct units in the result.
To do this, you would use the known ratio: 1 µg / 10-6 g. The solution would involve multiplying the given amount by this inverted ratio: (1.3 × 107 µg) × (1 g / 106 µg), which will give the result in grams.