Answer:
The substance half-life is of 4.98 days.
Step-by-step explanation:
Equation for an amount of a decaying substance:
The equation for the amount of a substance that decay exponentially has the following format:
In which k is the decay rate, as a decimal.
k-value of 0.1392.
This means that:
Find the substance's half life, in days.
This is t for which 
. So
The substance half-life is of 4.98 days.
Answer: 55 miles
Step-by-step explanation: Marcus goal is 80 miles for the week. he has already completed 25 miles of that goal so you would subtract 25 from 80 then you would find the miles still left
80-25=55
The answer would actually be A because if you make 3 1/4 a mixed number you would get 13/4 which equals 3.25. Now divide 3.25 by 4 because you will dividing these pizzas to 4 people. This gives me 0.8125. Then I would multiply 1/4 to 3.3125 which gives me 0.203125 and when you make this to an improper fraction it will come out to be 13/64 which is choice A. I hope this helps you! I am also sorry for what happened yesterday.
