Answer: 
Step-by-step explanation:
Given
Population of dust particle doubles every 30 minutes
If the initial sample is 21 grams
The model to predict the population will be

Where t=time in hours
A day has 24 hours . So, for 2 days time is 48 hours
Population is given by
Answer:
possibly china, but not confirmed.
Step-by-step explanation:
We can use the formula y2-y1/x2-x1 to find our answer. So, we have : t-16/5-2 = -3. We simplify that to t-16/3 = -3. We can then multiply both sides by 3 to get t-16 = -9. Then we can add 16 to both sides to get t = 7.
Answer:
3.25
Step-by-step explanation:
It would be a direct variation.