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:
564 pencils
Step-by-step explanation:
1 box = 12 pencils
25 boxes = 25 × 12 pencils = 300 pencils
22 boxes = 22 × 12 pencils = 264 pencils
300 + 264 = 564 pencils
Answer:
Step-by-step explanation:
|4r−12| = -(4r-12) when 4r-12< 0
4r< 12 so r<3
Answer:
Step-by-step explanation: We have to add how much time it took him to do all of his homework. To do this, we have to add 2/3 and 3/5.
First, we have to find a LCM between 3 and 5.
The LCM between those numbers are 15.
Next we find out what number to multiply 3 by to get 15, we multiply it by 5.
2 * 5 = 10
3 * 5 = 15
Next we find out what number to multiply 5 by to get 15, we multiply it by 3.
3 * 3 = 9
5 * 3 = 15
10/15+9/15=19/15
We are left off with 1 4/15
So it took him 1 hour and 4/15 minutes to do his homework.