Answer:
Any other language I don't know this language
The formula for the mass that remains:

m₀ - the initial mass, t - time, T - the half-life

The answer is c. 1.25 g.
Clarify what you mean by ratios?
Answer:
the speed of light in air is about 299,000,000 and 3×10⁸ m/s
1. earth
2. solar system
3. milky way galaxy
4. local group of galaxies
5. universe