Answer:
It’s A
Step-by-step explanation:
Answer:
Since the Y coordinate is constantly 9, it is a horizontal line.
Step-by-step explanation:
Answer:
We can use the sample about 42 days.
Step-by-step explanation:
Decay Equation:



Integrating both sides


When t=0, N=
= initial amount




.......(1)
.........(2)
Logarithm:
130 days is the half-life of the given radioactive element.
For half life,
,
days.
we plug all values in equation (1)






We need to find the time when the sample remains 80% of its original.







We can use the sample about 42 days.
1/2, 6/12, 9,/18, and 15/30
13=idk
14=first minutes into hour: 40/60=2/3
speed=distance/time
=280/(2/3)
ans=420miles/hour