The answer would be “D” because it’s is 4 less than 7j.
Answer: 41.5 min
Step-by-step explanation:
This problem can be solved with the Radioactive Half Life Formula:
(1)
Where:
is the final amount of the radioactive element
is the initial amount of the radioactive element
is the time elapsed
is the half life of the radioactive element
So, we need to substitute the given values and find from (1):
(2)
(3)
(4)
Applying natural logarithm in both sides:
(5)
(6)
Clearing :
This is the time elapsed
Second one if you distribute the first expression you get the second equation so the expressions are equivalent
The value of 2 in 2481 is 1000 less times the value of 2 in 5072
The circumference must be within half the difference of the average of those two numbers:
... |c -28.75| ≤ 0.25 . . . . where c is the circumference in inches
