For this case we must indicate the correct sign between the following numbers:

We have to:

So, we have to 
Answer:

If there are 4 people and you want the time for EACH person then you would do 62.59
Which = 15.6475
The answer is letter b. $5 for 1 sub!
If the half-life is t, then every t days, the amount of the radioactive isotope will be cut in half.
(1/2)^(number of half-lives) = 3%
number of half-lives = ln(0.03) / ln(0.5)
This gives the number of half-lives as 5.06.
Then 300 days = (5.06)(length of 1 half-life)
length of 1 half-life = 300 / 5.06 = 59.29 days