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:
c is the best answer of this question
Answer: 1st one
Step-by-step explanation:
In words:
Three sandwiches, each costing $5.25, equals 1/3 of Cassie's total money
We can write the formula:
(5.25*3)=1/3x
Now solve:
15.75=1/3x
3(15.75)=x
x=$47.25
Hope this helps!!
Answer:
Option (b) is the answer.
Step-by-step explanation:
If two distinct lines intersect
Then they are not parallel because parallel lines never intersect they go hand in hand
But since, we need to tell which is not true
So, option A is discarded.
Option (c) and (d) are also true hence, discarded.
Option (b) is correct that is the lines are perpendicular this is not true. hence, considered
Therefore, option (b) is the answer.